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Journal Cover European Journal of Medical Genetics
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   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1769-7212
   Published by Elsevier Homepage  [3089 journals]
  • Developmental and cytogenetic assessments of preimplantation embryos
           derived from in-vivo or in-vitro matured human oocytes
    • Abstract: Publication date: Available online 8 December 2017
      Source:European Journal of Medical Genetics
      Author(s): Farzaneh Fesahat, Seyed Mehdi Kalantar, Mohammad Hasan Sheikhha, Hojjatollah Saeedi, Fatemeh Montazeri, Razieh Dehghani Firouzabadi, Mohammad Ali Khalili
      Aneuploidy is of great relevance to embryo selection, as it represents one of the important causes of implantation failure. Furthermore, immature oocytes, retrieved during gonadotrophin-stimulated IVF cycles, are generally discarded in clinics; whereas, there was no detectable comprehensive evidence on higher rates of aneuploidy based on maturity status on the day of oocyte retrieval. As well, the correlation between embryo morphology on aneuploidy remains unclear. The aim was to evaluate the developmental and genetic integrity of human preimplantation embryos from rescue in-vitro matured MII stage oocytes as well as in vivo matured oocytes. 541 rescue in-vitro matured oocytes as case as well as 659 in-vivo matured oocytes as control were used for the developmental assay. Finally, 121 cleaved embryos with good quality were analyzed by FISH technique for the detection of chromosomes X, Y, 13, 15, 16, 18, 21 and 22. The fertilization rates were 61.62% and 61.76% in case and control groups, respectively. Also, embryo formation rates of 89.1% vs. 92.2% were recorded for case and control groups, respectively. Good quality embryos on day 3 were 62.54% in case and 68.36% in control groups. There were insignificant differences in fertilization, embryo formation and quality between the groups. Total abnormality in 35 of the 60 embryos was 58.5% in case and 62.3% in control (p < 0.05). There were significant differences between aneuploidy rates of embryos using only sex chromosome preimplantation genetic screening (PGS) and sex chromosome in combination with autosomal chromosomes PGS in case (58.5% vs 28.3%, p = 0.000) and control groups (62.3% vs 21.3%; p = 0.000). The results demonstrated that a high proportion of good quality embryos were aneuploid in both patient groups with no obvious increase in aneuploidies as a result of rescue IVM application. Furthermore, the morphological characteristics of embryos do not completely consistent with chromosomal content. Despite the Rescue IVM is currently not a routine procedure in association with IVF, our finding suggested a viable option for young infertile women facing cancellation of their IVF treatment due to ovarian over-response or resistance factors as well as patients with low functional ovarian reserve considering good quality of embryos from rescue IVM-MII oocytes.

      PubDate: 2017-12-12T06:57:28Z
       
  • Copy number variants in people with autism spectrum disorders and
           co-morbid psychosis
    • Abstract: Publication date: Available online 7 December 2017
      Source:European Journal of Medical Genetics
      Author(s): Felicity V. Larson, John R. Arrand, Digby Tantam, Peter B. Jones, Anthony J. Holland
      The genetic association between autism spectrum disorder (ASD) and psychotic disorders such as schizophrenia is complicated and mirrors the clinical overlap between these conditions to some degree. However, no studies to date have examined the genetics of individuals dually diagnosed with both ASD and psychosis. In this study, we present findings of copy number variants (CNVs) from a study of 116 well-characterised individuals with this dual diagnosis. DNA was extracted and arrayed using the Affymetrix CytoScan HD 2.8M array or the Affymetrix Cytogenetics arrays and compared with existing samples from the Database of Genomic Variants and the Simons Simplex Collection of CNVs from individuals with ASD and their families. Twenty-seven novel CNVs ≥20k base pairs were identified in the sample, most occurring in only a single individual, although two were found in two female participants. Forty-nine rare CNVs (<1.5% rate in general population) were also found at significantly higher frequencies than expected. The findings may provide evidence for areas of further study in the understanding of the development of both ASD and psychosis due to the number of affected genetic regions that have not previously been linked to these conditions.

      PubDate: 2017-12-12T06:57:28Z
       
  • Surprisingly good outcome in antenatal diagnosis of severe hydrocephalus
           related to CCDC88C deficiency
    • Abstract: Publication date: Available online 7 December 2017
      Source:European Journal of Medical Genetics
      Author(s): Mathew Wallis, Alessandra Baumer, Wiam Smaili, Imane Cherkaoui Jaouad, Abdelaziz Sefiani, Erica Jacobson, Lucy Bowyer, David Mowat, Anita Rauch
      Non-syndromic congenital hydrocephalus is aetiologically diverse and while a genetic cause is frequently suspected, it often cannot be confirmed. The most common genetic cause is L1CAM-related X-linked hydrocephalus and that explains only 5%–10% of all male cases. This underlines a current limitation in our understanding of the genetic burden of non-syndromic congenital hydrocephalus, especially for those cases with likely autosomal recessive inheritance. Additionally, the prognosis for most cases of severe congenital hydrocephalus is poor, with most of the surviving infants displaying significant intellectual impairment despite surgical intervention. It is for this reason that couples with an antenatal diagnosis of severe hydrocephalus are given the option, and may opt, for termination of the pregnancy. We present two families with CCDC88C-related recessive congenital hydrocephalus with children who had severe hydrocephalus. Those individuals who were shunted within the first few weeks of life, who did not require multiple surgical revisions, and who had a more distal truncating variant of the CCDC88C gene met their early childhood developmental milestones in some cases. This suggests that children with CCDC88C-related autosomal recessive hydrocephalus can have normal developmental outcomes under certain circumstances. We recommend CCDC88C analysis in cases of severe non-syndromic congenital hydrocephalus, especially when aqueduct stenosis with or without a medial diverticulum is seen, in order to aid prognosis discussion.

      PubDate: 2017-12-12T06:57:28Z
       
  • Pakistan Genetic Mutation Database (PGMD); A centralized Pakistani mutome
           data source
    • Abstract: Publication date: Available online 7 December 2017
      Source:European Journal of Medical Genetics
      Author(s): Iqbal Qasim, Bilal Ahmad, Muzammil Ahmad Khan, Niamatullah Khan, Noor Muhammad, Sulman Basit, Saadullah Khan
      The development and advancement of next generation sequencing have not only sped up the process of identifying rare variants, but have also enabled scientists to explore all variants in a single individual. The Pakistani population has a high ratio of first degree consanguinity, which is why it is a rich source for various kinds of genetic disorders. Due to the heterogeneous composition of Pakistani population, the likelihood of genetic heterogeneity for each disorder is high. Therefore, the compilation and organization of such vast genetic data is necessary to facilitate access for analysis and interpretation to researchers and medical geneticists. The increased research on Pakistani ethnic families for disease gene identification has revealed many mutations, which has led us to develop a Pakistani mutome database entitled “Pakistan Genetic Mutation Database (PGMD)”. In PGMD, the medico-genetic information about diseases are mainly compiled into Syndromic and Non-syndromic disorders. It is a public database, which can be freely accessed from http://www.pakmutation.com. At present, we have registered more than 1000 mutations, reported in about 130 different kinds of genetic disorders. Practically, PGMD will assist researchers, clinicians, and geneticists in genetic counseling and screening of population-specific mutations, which will also aid in personalized healthcare.

      PubDate: 2017-12-12T06:57:28Z
       
  • Redefining the phenotypic spectrum of de novo heterozygous CDK13 variants:
           Three patients without cardiac defects
    • Abstract: Publication date: Available online 6 December 2017
      Source:European Journal of Medical Genetics
      Author(s): Tomoko Uehara, Toshiki Takenouchi, Rika Kosaki, Kenji Kurosawa, Seiji Mizuno, Kenjiro Kosaki
      Recently, 7 patients with de novo constitutional non-synonymous mutations in the CDK13 gene were ascertained through a trio exome analysis of a large cohort of 610 patients with congenital cardiac diseases. Despite another report describing 9 additional patients, the clinical spectrum of this condition has yet to be defined. Herein, we report 3 patients with heterozygous constitutional CDK13 mutations, who were ascertained through exome analysis of children with intellectual disability and minor anomalies, who lacked cardiac anomalies. Two patients had a c.2149G > A, p.Gly717Arg mutation, and one had a c.2525A > G, p. Asn842Ser mutation. A review of the previously described patients and those described herein has enabled the following points to be clarified. First, congenital heart diseases are not an essential feature (13/19). Second, nasal features may help syndromic recognition (14/16). Third, widely spaced and peg-shaped teeth may represent a previously unappreciated diagnostic clue for this newly identified syndrome. Here, we show that p.Gly717Arg represents a hotspot in addition to p.Asn842Ser. We suggest that this CDK13-related disorder may represent a clinically recognizable syndrome.

      PubDate: 2017-12-12T06:57:28Z
       
  • A novel NR2F2 loss-of-function mutation predisposes to congenital heart
           defect
    • Abstract: Publication date: Available online 6 December 2017
      Source:European Journal of Medical Genetics
      Author(s): Xiao-Hui Qiao, Qian Wang, Juan Wang, Xing-Yuan Liu, Ying-Jia Xu, Ri-Tai Huang, Song Xue, Yan-Jie Li, Min Zhang, Xin-Kai Qu, Ruo-Gu Li, Xing-Biao Qiu, Yi-Qing Yang
      Congenital heart defect (CHD) is the most common type of birth defect in humans and a leading cause of infant morbidity and mortality. Previous studies have demonstrated that genetic defects play a pivotal role in the pathogenesis of CHD. However, the genetic basis of CHD remains poorly understood due to substantial genetic heterogeneity. In this study, the coding exons and splicing boundaries of the NR2F2 gene, which encodes a pleiotropic transcription factor required for normal cardiovascular development, were sequenced in 168 unrelated patients with CHD, and a novel mutation (c.247G > T, equivalent to p.G83X) was detected in a patient with double outlet right ventricle as well as ventricular septal defect. Genetic scanning of the mutation carrier's relatives available showed that the mutation was present in all affected family members but absent in unaffected family members. Analysis of the index patient's pedigree displayed that the mutation co-segregated with CHD, which was transmitted as an autosomal dominant trait with complete penetrance. The nonsense mutation was absent in 230 unrelated, ethnically-matched healthy individuals used as controls. Functional deciphers by using a dual-luciferase reporter assay system revealed that the mutant NR2F2 protein had no transcriptional activity as compared with its wild-type counterpart. Furthermore, the mutation abrogated the synergistic transcriptional activation between NR2F2 and GATA4, another core cardiac transcription factor associated with CHD. This study firstly associates NR2F2 loss-of-function mutation with an increased susceptibility to double outlet right ventricle in humans, which provides further significant insight into the molecular mechanisms underpinning CHD, suggesting potential implications for genetic counseling of CHD families and personalized treatment of CHD patients.

      PubDate: 2017-12-12T06:57:28Z
       
  • Potential pathogenic mechanisms underlying Fragile X Tremor Ataxia
           Syndrome: RAN translation and/or RNA gain-of-function'
    • Abstract: Publication date: Available online 6 December 2017
      Source:European Journal of Medical Genetics
      Author(s): Manon Boivin, Rob Willemsen, Renate K. Hukema, Chantal Sellier
      Fragile X-associated tremor/ataxia syndrome (FXTAS) is an inherited neurodegenerative disease caused by an expansion of 55–200 CGG repeats located in the FMR1 gene. The main clinical and neuropathological features of FXTAS are progressive intention tremor and gait ataxia associated with brain atrophy, neuronal cell loss and presence of ubiquitin-positive intranuclear inclusions in both neurons and astrocytes. At the molecular level, FXTAS is characterized by increased expression of FMR1 sense and antisense RNA containing expanded CGG or GGC repeats, respectively. Here, we discuss the putative molecular mechanisms underlying FXTAS and notably recent reports that expanded CGG and GGC repeats may be pathogenic through RAN translation into toxic proteins.

      PubDate: 2017-12-12T06:57:28Z
       
  • Pathogenic commonalities between spinal muscular atrophy and amyotrophic
           lateral sclerosis: Converging roads to therapeutic development
    • Abstract: Publication date: Available online 5 December 2017
      Source:European Journal of Medical Genetics
      Author(s): Melissa Bowerman, Lyndsay M. Murrray, Frédérique Scamps, Bernard L. Schneider, Rashmi Kothary, Cédric Raoul
      Spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS) are the two most common motoneuron disorders, which share typical pathological hallmarks while remaining genetically distinct. Indeed, SMA is caused by deletions or mutations in the survival motor neuron 1 (SMN1) gene whilst ALS, albeit being mostly sporadic, can also be caused by mutations within genes, including superoxide dismutase 1 (SOD1), Fused in Sarcoma (FUS), TAR DNA-binding protein 43 (TDP-43) and chromosome 9 open reading frame 72 (C9ORF72). However, it has come to light that these two diseases may be more interlinked than previously thought. Indeed, it has recently been found that FUS directly interacts with an Smn-containing complex, mutant SOD1 perturbs Smn localization, Smn depletion aggravates disease progression of ALS mice, overexpression of SMN in ALS mice significantly improves their phenotype and lifespan, and duplications of SMN1 have been linked to sporadic ALS. Beyond genetic interactions, accumulating evidence further suggests that both diseases share common pathological identities such as intrinsic muscle defects, neuroinflammation, immune organ dysfunction, metabolic perturbations, defects in neuron excitability and selective motoneuron vulnerability. Identifying common molecular effectors that mediate shared pathologies in SMA and ALS would allow for the development of therapeutic strategies and targeted gene therapies that could potentially alleviate symptoms and be equally beneficial in both disorders. In the present review, we will examine our current knowledge of pathogenic commonalities between SMA and ALS, and discuss how furthering this understanding can lead to the establishment of novel therapeutic approaches with wide-reaching impact on multiple motoneuron diseases.

      PubDate: 2017-12-12T06:57:28Z
       
  • A higher rare CNV burden in the genetic background potentially contributes
           to intellectual disability phenotypes in 22q11.2 deletion syndrome
    • Abstract: Publication date: Available online 28 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Matthew Jensen, Frank R. Kooy, Tony Simon, Edwin Reyniers, Santhosh Girirajan, Flora Tassone
      The 22q11.2 deletion syndrome (22q11DS), the most common survivable human genetic deletion disorder, is caused by a hemizygous deletion of 30–40 contiguous genes on chromosome 22, many of which have not been well characterized. Clinical features seen in patients with this deletion, including intellectual disability, are not completely penetrant and vary in severity between patients, suggesting the involvement of variants elsewhere in the genome in the manifestation of the phenotype. Given that it is a relatively rare disorder (1/2000-6000 in humans), limited research has shed light into the contribution of these second-site variants to the developmental pathogenesis that underlies 22q11DS. As CNVs throughout the genome might constitute such a genetic risk factor for variability in the 22q11DS phenotypes such as intellectual disability, we sought to determine if the overall burden of rare CNVs in the genetic background influenced the phenotypic variability. We analyzed CNV and clinical data from 66 individuals with 22q11DS, and found that 77% (51/66) of individuals with the 22q11DS also carry additional rare CNVs (<0.1% frequency). We observed several trends between CNV burden and phenotype, including that the burden of large rare CNVs (>200 Kb in size) was significantly higher in 22q11DS individuals with intellectual disability than with normal IQ. Our analysis shows that rare CNVs may contribute to intellectual disability 22q11DS, and further analysis on larger 22q11DS cohorts should be performed to confirm this correlation.

      PubDate: 2017-12-01T06:06:09Z
       
  • Atopic disorders in CHARGE syndrome: A retrospective study and literature
           review
    • Abstract: Publication date: Available online 27 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Fang Kong, Donna M. Martin
      Background Atopic disorders have been reported in CHARGE syndrome, but the prevalence and underlying mechanisms are not known. Methods We performed a retrospective study of atopic disorders in 23 individuals with CHARGE syndrome, and reviewed other published reports of atopic disorders in CHARGE syndrome. We assayed for enrichment of atopic disorders in CHARGE syndrome based on gender and presence of a CHD7 pathogenic variant. Results In our cohort, 65% (15/23) of individuals with CHARGE syndrome were found to have a pathogenic CHD7 variant. Overall, 65% (15/23) of individuals with CHARGE had atopic disorders. Among the 23 individuals with CHARGE, 22% (5/23) had food allergy, 26% (6/23) exhibited drug allergy, 22% (5/23) had contact allergy, 9% (2/23) had allergic rhinitis, and 22% (5/23) had asthma. In our cohort, the proportion of males to females with CHARGE and atopic disorders was 11:4 (P < 0.01), and there was no significant difference between atopic disorders in individuals with CHD7 pathogenic variants and those without CHD7 pathogenic variants (P > 0.05). Conclusion In our cohort of 23 individuals with CHARGE syndrome, 15 (65%) exhibited atopic disorders, with a slight male predominance.

      PubDate: 2017-12-01T06:06:09Z
       
  • A report of three families with FBN1-related acromelic dysplasias and
           review of literature for genotype-phenotype correlation in gelophysic
           dysplasia
    • Abstract: Publication date: Available online 27 November 2017
      Source:European Journal of Medical Genetics
      Author(s): S.W. Cheng, Ho-Ming Luk, YoYo W.Y. Chu, Yuet-Ling Tung, Elanie Yin-Wah Kwan, Ivan Fai-Man Lo, Brian Hon-Yin Chung
      Acromelic dysplasia is a heterogeneous group of rare skeletal dysplasias characterized by distal limb shortening. Weill-Marchesani syndrome (WMS), Geleophysic dysplasia (GD) and Acromicric dysplasia (AD) are clinically distinct entities within this group of disorders and are characterized by short stature, short hands, stiff joints, skin thickening, facial anomalies, normal intelligence and skeletal abnormalities. Mutations of the Fibrillin-1 (FBN1) gene have been reported to cause AD, GD and related phenotypes. We reported three families with acromelic short stature. FBN1 analysis showed that all affected individuals carry a heterozygous missense mutation c.5284G > A (p.Gly1762Ser) in exon 42 of the FBN1 gene. This mutation was previously reported to be associated with GD. We reviewed the literature and compared the clinical features of the patients with FBN1 mutations to those with A Distintegrin And Metalloproteinase with Thrombospondin repeats-like 2 gene (ADAMTSL2) mutations. We found that tip-toeing gait, long flat philtrum and thin upper upper lip were more consistently found in GD patients with ADAMTSL2 mutations than in those with FBN1 mutations. The results have shed some light on the phenotype-genotype correlation in this group of skeletal disorders. A large scale study involving multidisciplinary collaboration would be needed to consolidate our findings.

      PubDate: 2017-12-01T06:06:09Z
       
  • Recontacting in light of new genetic diagnostic techniques for patients
           with intellectual disability: Feasibility and parental perspectives
    • Abstract: Publication date: Available online 27 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Gea Beunders, Melodi Dekker, Oscar Haver, Hanne J. Meijers-Heijboer, Lidewij Henneman
      A higher diagnostic yield from new diagnostic techniques makes re-evaluation in patients with intellectual disability without a causal diagnosis valuable, and is currently only performed after new referral. Active recontacting might serve a larger group of patients. We aimed to evaluate parental perspectives regarding recontacting and its feasibility in clinical genetic practice. A recontacting pilot was performed in two cohorts of children with intellectual disability. In cohort A, parents were recontacted by phone and in cohort B by letter, to invite them for a re-evaluation due to the new technologies (array CGH and exome sequencing, respectively). Parental opinions, preferences and experiences with recontacting were assessed by a self-administered questionnaire, and the feasibility of this pilot was evaluated. 47 of 114 questionnaires were returned. In total, 87% of the parents believed that all parents should be recontacted in light of new insights, 17% experienced an (positive or negative) emotional reaction. In cohort A, approached by phone, 36% made a new appointment for re-evaluation, and in cohort B, approached by letter, 4% did. Most parents have positive opinions on recontacting. Recontacting might evoke emotional responses that may need attention. Recontacting is feasible but time-consuming and a large additional responsibility for clinical geneticists.

      PubDate: 2017-12-01T06:06:09Z
       
  • Novel mutations and a severe neurological phenotype in Sjögren-Larsson
           syndrome patients from Iran
    • Abstract: Publication date: Available online 26 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Ariana Kariminejad, Mohammadreza Barzgar, Bita Bozorgmehr, Elham Keshavarz, Mohamad Hasan Kariminejad, Dana S'Aulis, William B. Rizzo
      Sjögren-Larsson syndrome (SLS) is a rare autosomal recessive disorder characterized by ichthyosis, spasticity and intellectual disability. The disease is caused by mutations in the ALDH3A2 gene that encodes fatty aldehyde dehydrogenase. We describe 7 Iranian SLS patients from 5 unrelated consanguineous families. Sequencing of ALDH3A2 identified 4 novel mutations, including a 26-bp deletion (c.25_50del), small in-frame deletion (c.370_372del; p.G124del), a termination (p.Q35Ter) and a missense mutation (p.Lys211Glu). Bacterial expression of the p.Lys211Glu and p.G124del mutations showed little or no detectable enzyme activity. Three of the patients exhibited an unusual neuro-regressive clinical course associated with seizures, which may reflect the presence of unidentified genetic or environmental modifiers in this consanguineous population. This cohort represents the largest group of Iranian patients with molecularly confirmed SLS and expands the mutational and clinical spectrum of this disease.

      PubDate: 2017-12-01T06:06:09Z
       
  • A complex phenotype in a family with a pathogenic SOX3 missense variant
    • Abstract: Publication date: Available online 24 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Anne M. Jelsig, Birgitte R. Diness, S. Sven Kreiborg, Katharina Main, Vibeke A. Larsen, Hanne Hove
      Duplications and deletions of Xq26-27 including SOX3 (Xq27.1) have been associated with X-linked mental retardation and isolated growth hormone deficiency (OMIM 300123) or X-linked panhypopituitarism (OMIM 312000). Yet, pathogenic point mutations seem to be extremely rare. We report a family with three affected males with several clinical features including mild intellectual disability, microphthalmia, coloboma, hypopituitarism, facial dysmorphology and dental anomalies, including microcephaly, retrognathia and a solitary median maxillary central incisor amongst other features. Using Whole Exome Sequencing a missense variant in SOX3, NM_005634.2:c.449C>A; p.(Ser150Tyr) was identified. Segregation analysis in the family demonstrated that the variant was inherited through healthy females with its origin in the maternal grandmother showing germline mosaicism. Thus, we report one of the first cases of a pathogenic variant in SOX3 and germline mosaicism of this variant.

      PubDate: 2017-12-01T06:06:09Z
       
  • Molecular cytogenetics characterization of seven small supernumerary
           marker chromosomes derived from chromosome 19: Genotype-phenotype
           correlation and review of the literature
    • Abstract: Publication date: Available online 23 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Maria Paola Recalcati, Maria Teresa Bonati, Nicola Beltrami, Laura Cardarelli, Ilaria Catusi, Asia Costa, Maria Garzo, Isabella Mammi, Teresa Mattina, Elisa Nalesso, Anna Maria Nardone, Diana Postorivo, Anna Sajeva, Aminta Varricchio, Annapia Verri, Nicoletta Villa, Lidia Larizza, Daniela Giardino
      Only a few subjects carrying supernumerary marker chromosomes derived from 19 chromosome (sSMC(19)) have been described to date and for a small portion of them the genic content has been defined at the molecular level. We present seven new different sSMCs(19) identified in eight individuals, seven of whom unrelated. The presence of the sSMC is associated with a clinical phenotype in five subjects, while the other three carriers, two of whom related, are normal. All sSMCs(19) have been characterized by means of conventional and molecular cytogenetics. We compare the sSMCs(19) carriers with a clinical phenotype to already described patients with gains (sSMCs or microduplications) of overlapping genomic regions with the aim to deepen the pathogenicity of the encountered imbalances and to assess the role of the involved genes on the phenotype. The present work supports the correlation between the gain of some chromosome 19 critical regions and specific phenotypes.

      PubDate: 2017-12-01T06:06:09Z
       
  • Novel GNB1 de novo mutation in a patient with neurodevelopmental disorder
           and cutaneous mastocytosis: Clinical report and literature review
    • Abstract: Publication date: Available online 23 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Krzysztof Szczałuba, Anna Biernacka, Krystyna Szymańska, Piotr Gasperowicz, Joanna Kosińska, Małgorzata Rydzanicz, Rafał Płoski
      De novo monoallelic mutations in the GNB1 gene, encoding a β subunit of heterotrimeric G proteins, cause a newly recognized disorder with the typical clinical picture of severe developmental delay/intellectual disability, hypotonia and extrapyramidal symptoms. We describe another case of the condition with manifestations of cutaneous mastocytosis associated with a novel do novo mutation GNB1 NM_001282539.1: c.230G > T; p.(Gly77Val). We also present the detailed clinical and etiopathogenetic discussion on previously diagnosed patients as well as suggestions for the link of the mutation with skin disease.

      PubDate: 2017-12-01T06:06:09Z
       
  • Pancreatic hemi-agenesis in MEN1: A clinical report
    • Abstract: Publication date: Available online 23 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Wouter J. Vinck, Frank Van de Mierop, François Van Mieghem, Maarten Vinck, Herman Becq, Geneviève Michils
      We first describe a patient with multiple endocrine neoplasia type 1 (MEN1) and dorsal pancreatic hemi-agenesis. Previously, pancreas divisum has been reported in MEN1. Recent data in mice have elucidated the molecular mechanisms of pancreatic endoderm specification. Disinhibition of hedgehog signaling appears to be important in how Gata4 and Gata6 variants cause pancreatic agenesis. Disinhibition of hedgehog signaling has also been observed in Men1 knockout pancreatic islets. Although we cannot exclude a spurious association between dorsal pancreatic hemi-agenesis and MEN1 in our patient, we argue that developmental abnormalities of the pancreas may have to be considered as possibly related to the MEN1 phenotype.

      PubDate: 2017-12-01T06:06:09Z
       
  • Missense mutation of TTC7A mimicking tricho-hepato-enteric (SD/THE)
           syndrome in a patient with very-early onset inflammatory bowel disease
    • Abstract: Publication date: Available online 23 November 2017
      Source:European Journal of Medical Genetics
      Author(s): João Farela Neves, Isabel Afonso, Luis Borrego, Catarina Martins, Ana Isabel Cordeiro, Conceição Neves, Caroline Lacoste, Catherine Badens, Alexandre Fabre
      Tricho-hepato-enteric syndrome (SD/THE) and Multiple intestinal atresia with combined immune deficiency (MIA-CID) are autosomal recessive disorders that present immunological and gastrointestinal features. There are two different phenotypes of patients with TTC7A mutations: the severe form, caused by null mutations and leading to the classical MIA-CID; and the mild form, caused by missense mutations and leading to predominant features of VEO-IBD, less severe immunological involvement and hair abnormalities. We expand the knowledge about TTC7A deficiency, describing a patient with the mild phenotype of TTC7A deficiency but presenting overlapping features of SD/THE and MIA-CID: intestinal atresia and inflammatory bowel disease evocative of MIA-CID, but also dental abnormalities, huge forehead, liver abnormalities, autoimmune thyroiditis and hypogammaglobulinemia, evocative of SD/THE.

      PubDate: 2017-12-01T06:06:09Z
       
  • Uncommon runs of homozygosity disclose homozygous missense mutations in
           two ciliopathy-related genes (SPAG17 and WDR35) in a patient with multiple
           brain and skeletal anomalies
    • Abstract: Publication date: Available online 23 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Carlos Córdova-Fletes, Luis E. Becerra-Solano, Martha M. Rangel-Sosa, Ana María Rivas-Estilla, Kame Alberto Galán-Huerta, Rocío Ortiz-López, Augusto Rojas-Martínez, Clara I. Juárez-Vázquez, José E. García-Ortiz
      We describe a patient severely affected with multiple congenital anomalies, including brain malformations and skeletal dysplasia suggestive of cranioectodermal dysplasia (CED) ciliopathy, who unusually carries several homozygosity tracts involving homozygous missense mutations in SPAG17 (exon 8; c.1069G > C; p.Asp357His) and WDR35 (exon 13; c.1415G > A; p.Arg472Gln) as revealed by homozygosity mapping and next generation sequencing. SPAG17 is essential for the function and structure of motile cilia, while WDR35 belongs to the same intraflagellar transport (IFT) gene family whose protein products are part of functional IFT A and B complexes. Formerly, SPAG17 was related – through polymorphic variants – to an influence on individuals’ height; more recently, Spag17−/− mice models were reported to present skeletal and bone defects, reduced mucociliary clearance, respiratory distress, and cerebral ventricular enlargement. Homozygous or compound heterozygous mutations in WDR35 have mainly been related to CED2 or short-rib thoracic dysplasia 7, with only three cases showing some brain anomalies. Given that our patient presents these clinical features and the close functional relationship between SPAG17 and WDR35, it is feasible that the combined effects from both mutations contribute to his phenotype. To our knowledge, this patient is the first to harbor a likely pathogenic homozygous mutation in both genes at the same time. Thus, the resulting complex phenotype of this patient illustrates the heterogeneity associated with ciliopathies and further expands the clinical and mutational spectrum of these diseases. Finally, we highlight the combined use of high-throughput tools to diagnose and support the proper handling of this and other patients.

      PubDate: 2017-12-01T06:06:09Z
       
  • Rare copy number variants identified in prune belly syndrome
    • Abstract: Publication date: Available online 23 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Nansi S. Boghossian, Robert J. Sicko, Andreas Giannakou, Aggeliki Dimopoulos, Michele Caggana, Michael Y. Tsai, Edwina H. Yeung, Nathan Pankratz, Benjamin R. Cole, Paul A. Romitti, Marilyn L. Browne, Ruzong Fan, Aiyi Liu, Denise M. Kay, James L. Mills
      Prune belly syndrome (PBS), also known as Eagle-Barrett syndrome, is a rare congenital disorder characterized by absence or hypoplasia of the abdominal wall musculature, urinary tract anomalies, and cryptorchidism in males. The etiology of PBS is largely unresolved, but genetic factors are implicated given its recurrence in families. We examined cases of PBS to identify novel pathogenic copy number variants (CNVs). A total of 34 cases (30 males and 4 females) with PBS identified from all live births in New York State (1998–2005) were genotyped using Illumina HumanOmni2.5 microarrays. CNVs were prioritized if they were absent from in-house controls, encompassed ≥10 consecutive probes, were ≥20 Kb in size, had ≤20% overlap with common variants in population reference controls, and had ≤20% overlap with any variant previously detected in other birth defect phenotypes screened in our laboratory. We identified 17 candidate autosomal CNVs; 10 cases each had one CNV and four cases each had two CNVs. The CNVs included a 158 Kb duplication at 4q22 that overlaps the BMPR1B gene; duplications of different sizes carried by two cases in the intron of STIM1 gene; a 67 Kb duplication 202 Kb downstream of the NOG gene, and a 1.34 Mb deletion including the MYOCD gene. The identified rare CNVs spanned genes involved in mesodermal, muscle, and urinary tract development and differentiation, which might help in elucidating the genetic contribution to PBS. We did not have parental DNA and cannot identify whether these CNVs were de novo or inherited. Further research on these CNVs, particularly BMP signaling is warranted to elucidate the pathogenesis of PBS.

      PubDate: 2017-12-01T06:06:09Z
       
  • Desmosterolosis presenting with multiple congenital anomalies
    • Abstract: Publication date: Available online 23 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Mersedeh Rohanizadegan, Stephanie Sacharow
      Desmosterolosis is a rare multiple congenital anomaly syndrome caused by defect in the enzyme 3-beta-hydroxysterol delta-24-reductase (DHCR24) in the cholesterol biosynthesis pathway. Defects in this enzyme cause increased level of the cholesterol precursor desmosterol while disrupting development of cholesterol, impacting embryogenesis. A total of 9 cases of desmosterolosis have been reported to date. We report a 20-month-old male from consanguineous parents with multiple congenital anomalies including corpus callosum hypoplasia, facial dysmorphism, cleft palate, pectus deformity, short, wide neck and distal contractures. On analysis of the regions of homozygosity found by microarray, we identified DHCR24 as a candidate gene. Sterol quantitation showed a desmosterol level of 162 μg/mL (nl: 0.82 ± 0.48). Genetic testing confirmed the diagnosis with a homozygous likely pathogenic mutation (p.Glu191Lys) in the DHCR24 gene. Our case expands the known diagnostic spectrum for Desmosterolosis. We suggest considering Desmosterolosis in the differential diagnosis of patients who present with concurrent agenesis of the corpus callosum with white matter atrophy and ventriculomegaly, retromicrognathia with or without cleft palate, hand contractures, and delay of growth and development. Children of consanguineous mattings may be at higher risk for rare recessive disorders and testing for cholesterol synthesis defect should be a consideration for affected children. Initial evaluation can be performed using sterol quantitation, followed by genetic testing.

      PubDate: 2017-12-01T06:06:09Z
       
  • Additional features of Gillespie syndrome in two Brazilian siblings with a
           novel ITPR1 homozygous pathogenic variant
    • Abstract: Publication date: Available online 21 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Daniel R. Carvalho, João Eugenio G. Medeiros, Daniela Sebestyan M. Ribeiro, Bernardo J.A.F. Martins, Nara L.M. Sobreira
      Gillespie syndrome (GS) [MIM: 206700] is a very rare condition characterized by bilateral iris defect, congenital hypotonia, cerebellar ataxia and intellectual disability. The typical iris anomaly is considered necessary to the diagnosis of GS. Recently, variants in ITPR1 were described causing GS. Non-neurological features were reported in few patients. Here we describe two consanguineous siblings with GS and a novel homozygous ITPR1 pathogenic variant (p.N984fs). They also present a cardiac defect (pulmonary valve stenosis) and one sib had a genitourinary malformation (ureteropelvic junction obstruction). Our report reinforces ITPR1 as the cause of GS and suggests a possible role of ITPR1 in the development of other organs.

      PubDate: 2017-12-01T06:06:09Z
       
  • A comparison of splicing assays to detect an intronic variant of the OCRL
           gene in Lowe syndrome
    • Abstract: Publication date: December 2017
      Source:European Journal of Medical Genetics, Volume 60, Issue 12
      Author(s): Keita Nakanishi, Kandai Nozu, Ryugo Hiramoto, Shogo Minamikawa, Tomohiko Yamamura, Junya Fujimura, Tomoko Horinouchi, Takeshi Ninchoji, Hiroshi Kaito, Naoya Morisada, Shingo Ishimori, Koichi Nakanishi, Ichiro Morioka, Hiroyuki Awano, Masafumi Matsuo, Kazumoto Iijima
      Lowe syndrome is an X-linked inherited disorder diagnosed by congenital cataracts, intellectual impairment, and renal tubular dysfunction. It is caused by pathogenic variants of the oculocerebrorenal syndrome of Lowe gene (OCRL), of which more than 250 have been reported so far. Around 30 of these variants are intronic nucleotide changes; however, to show the pathogenicity of these variants is usually laborious. In this report, we conducted genetic testing of a patient clinically diagnosed with Lowe syndrome to detect the presence of OCRL variants. We analyzed variant transcript expression in peripheral blood leukocytes and using a minigene construct in addition to in silico analysis. We detected a 9 base pair intronic insertion between OCRL exon 10 and exon 11 derived from the alteration of the splicing acceptor site in intron 10 caused by the intronic splicing variant NM_000276.3: c.940-11G>A (p.Lys313_Val314insAsnSer*). The findings obtained from transcript analysis of peripheral blood leukocytes and the minigene construct assay were identical to those of in silico analysis. All assays detected the same transcript abnormality and were reliable in revealing the pathogenicity of the intronic variant. The in vitro assay can also be used to clarify the complicated splicing mechanisms in inherited kidney diseases.

      PubDate: 2017-11-18T20:21:04Z
       
  • Very early onset inflammatory bowel disease: Investigation of the IL-10
           signaling pathway in Iranian children
    • Abstract: Publication date: December 2017
      Source:European Journal of Medical Genetics, Volume 60, Issue 12
      Author(s): Shahram Nemati, Shahram Teimourian, Mina Tabrizi, Mehri Najafi, Naghi Dara, Farid Imanzadeh, Mitra Ahmadi, Maryam Kazemi Aghdam, Mohmoud Tavassoli, Pejman Rohani, Seyyed Ramin Madani, Martin de Boer, T.W. Kuijpers, Dirk Roos
      Background & aim Comparing to adult inflammatory bowel disease (IBD), those with early onset manifestations have different features in terms of the underlying molecular pathology, the course of disease and the response to therapy. We investigated the IL-10 signaling pathway previously reported as an important cause of infantile (Very Early Onset) IBD to find any possible variants. Method With the next generation sequencing technique we screened IL-10, IL-10RA and IL10RB genes of 15 children affected by very early onset-GI (gastrointestinal) disorders. Additionally, we analyzed them based on Thermo Fisher immune deficiency panel for genes either having a known role in IBD pathogenesis or cause the disorders with overlapping manifestations. We performed multiple functional analyses only for the cases showing variants in IL-10- related genes. Result In 3 out of 15 patients we identified variants including a homozygous and heterozygote mutations in IL-10RA and a novel homozygous mutation in IL-12RB1. Our functional studies reveal that in contrast to the IL-10RA heterozygote mutation that does not have deleterious effects, the homozygous mutation abrogates the IL-10 signaling pathway. Conclusion Our study suggests we need to modify the classical diagnostic approach from functional assays followed by candidate- gene or genes sequencing to the firstly parallel genomic screening followed by functional studies.

      PubDate: 2017-11-18T20:21:04Z
       
  • Efficient detection of chromosome imbalances and single nucleotide
           variants using targeted sequencing in the clinical setting
    • Abstract: Publication date: December 2017
      Source:European Journal of Medical Genetics, Volume 60, Issue 12
      Author(s): Darine Villela, Silvia Souza Costa, Angela M. Vianna-Morgante, Ana C.V. Krepischi, Carla Rosenberg
      We evaluated an approach to detect copy number variants (CNVs) and single nucleotide changes (SNVs), using a clinically focused exome panel complemented with a backbone and SNP probes that allows for genome-wide copy number changes and copy-neutral absence of heterozygosity (AOH) calls; this approach potentially substitutes the use of chromosomal microarray testing and sequencing into a single test. A panel of 16 DNA samples with known alterations ranging from megabase-scale CNVs to single base modifications were used as positive controls for sequencing data analysis. The DNA panel included CNVs (n = 13) of variable sizes (23 Kb to 27 Mb), uniparental disomy (UPD; n = 1), and single point mutations (n = 2). All DNA sequence changes were identified by the current platform, showing that CNVs of at least 23 Kb can be properly detected. The estimated size of genomic imbalances detected by microarrays and next generation sequencing are virtually the same, indicating that the resolution and sensitivity of this approach are at least similar to those provided by DNA microarrays. Accordingly, our data show that the combination of a sequencing platform comprising focused exome and whole genome backbone, with appropriate algorithms, enables a cost-effective and efficient solution for the simultaneous detection of CNVs and SNVs.

      PubDate: 2017-11-18T20:21:04Z
       
  • A novel mutation in CDK5RAP2 gene causes primary microcephaly with speech
           impairment and sparse eyebrows in a consanguineous Pakistani family
    • Abstract: Publication date: December 2017
      Source:European Journal of Medical Genetics, Volume 60, Issue 12
      Author(s): Uzma Abdullah, Muhammad Farooq, Yuan Mang, Syeda Marriam Bakhtiar, Ambrin Fatima, Lars Hansen, Klaus Wilbrandt Kjaer, Lars Allan Larsen, Sanam Faryal, Niels Tommerup, Shahid Mahmood Baig
      CDK5RAP2 gene encodes a centrosomal protein, highly expressed in fetal brain and essentially indispensable for its normal development, as biallelic mutations in it lead to primary microcephaly (MCPH). Despite being known as MCPH linked gene for more than a decade, the phenotypic spectrum of CDK5RAP2 mutations is still under explored as only eleven families have been reported worldwide. Here, we analyzed a consanguineous Pakistani MCPH family, characterized by moderate to severe intellectual disability, speech impairment, moderately short stature and sparse eyebrows. Whole exome sequencing of the proband identified a 2bp duplication in exon 34 of CDK5RAP2 that causes frame-shift, leading to a premature stop codon. The resultant transcript is resistant to nonsense mediated decay, suggesting that the mutation leads to a truncated protein lacking C-terminal domains; CDK5R1, and Cnn motif 2 (CM2), required for its localization to centrosome and Golgi Apparatus. Clinical variability observed in the family highlights the importance of further detailed clinical description of patients with CDK5RAP2 mutations.

      PubDate: 2017-11-18T20:21:04Z
       
  • Novel compound heterozygous mutations identified by whole exome sequencing
           in a Japanese patient with geroderma osteodysplastica
    • Abstract: Publication date: December 2017
      Source:European Journal of Medical Genetics, Volume 60, Issue 12
      Author(s): Ryojun Takeda, Masaki Takagi, Hiroyuki Shinohara, Hiroshi Futagawa, Satoshi Narumi, Tomonobu Hasegawa, Gen Nishimura, Hiroshi Yoshihashi
      Geroderma osteodysplastica (GO) is a subtype of cutis laxa syndrome characterized by congenital wrinkly skin, a prematurely aged face, extremely short stature, and osteoporosis leading to recurrent fractures. GO exhibits an autosomal recessive inheritance pattern and is caused by loss-of-function mutations in GORAB, which encodes a protein important for Golgi-related transport. Using whole exome sequencing, we identified novel compound heterozygous nonsense mutations in the GORAB in a GO patient. The patient was a 14-year-old Japanese boy. Wrinkled skin and joint laxity were present at birth. At 1 year of age, he was clinically diagnosed with cutis laxa syndrome based on recurrent long bone fractures and clinical features, including wrinkled skin, joint laxity, and a distinctive face. He did not show retarded gross motor and cognitive development. At 11 years of age, he was treated with oral bisphosphonate and vitamin D owing to recurrent multiple spontaneous fractures of the vertebral and extremity bones associated with a low bone mineral density (BMD). Bisphosphonate treatment improved his BMD and fracture rate. Whole exome sequencing revealed two novel compound heterozygous nonsense mutations in the GORAB gene (p.Arg60* and p.Gln124*), and the diagnosis of GO was established. GO is a rare connective tissue disorder. Approximately 60 cases have been described to date, and this is the first report of a patient from Japan. Few studies have reported the effects of bisphosphonate treatment in GO patients with recurrent spontaneous fractures. Based on this case study, we hypothesize that oral bisphosphonate and vitamin D are effective and safe treatment options for the management of recurrent fractures in GO patients. It is important to establish a precise diagnosis of GO to prevent recurrent fractures and optimize treatment plans.

      PubDate: 2017-11-18T20:21:04Z
       
  • Mutations in DDHD1, encoding a phospholipase A1, is a novel cause of
           retinopathy and neurodegeneration with brain iron accumulation
    • Abstract: Publication date: December 2017
      Source:European Journal of Medical Genetics, Volume 60, Issue 12
      Author(s): Rodolphe Dard, Claire Meyniel, Valérie Touitou, Giovanni Stevanin, Foudil Lamari, Alexandra Durr, Claire Ewenczyk, Fanny Mochel
      Defects of phospholipids remodelling and synthesis are inborn errors of metabolism responsible for various clinical presentations including spastic paraplegia, retinopathy, optic atrophy, myo- and cardiomyopathies, and osteo-cutaneous manifestations. DDHD1 encodes a phospholipase A1, which is involved in the remodelling of phospholipids. We previously described a relatively pure hereditary spastic paraplegia (HSP) phenotype associated with mutations in DDHD1. Here we report a complex form of HSP associated with retinal dystrophy and a pattern of neurodegeneration with brain iron accumulation (NBIA) on brain MRI, due to a novel homozygous mutation in DDHD1. This observation enlarges the clinical spectrum of DDHD1-associated disorders and sheds light on a new aetiology for syndromes associating retinopathy and NBIA. It also emphasizes the role of complex lipids in the retina.

      PubDate: 2017-11-18T20:21:04Z
       
  • Familial 9q33q34 microduplication in siblings with developmental disorders
           and macrocephaly
    • Abstract: Publication date: December 2017
      Source:European Journal of Medical Genetics, Volume 60, Issue 12
      Author(s): Keiko Shimojima, Nobuhiko Okamoto, Himanshu Goel, Yumiko Ondo, Toshiyuki Yamamoto
      Because several genes responsible for epileptic encephalopathy are located on the 9q33q34 region, patients with chromosomal deletions of this region often show intractable epilepsy and neurodevelopmental disability. Contrary to these findings, chromosomal duplications of this region have never been reported previously. We identified a first case of 9q33q34 microduplications in siblings associated with developmental disorders and macrocephaly. Their mother was a mosaic carrier of this duplication. Duplicated regions involved STXBP1; the gene related to epileptic encephalopathy. Neurological features including developmental delay and macrocephaly observed in the present siblings may be derived from the extra-copy of STXBP1.

      PubDate: 2017-11-18T20:21:04Z
       
  • Gait disturbance and lower limb pain in a patient with PIK3CA-related
           disorder
    • Abstract: Publication date: December 2017
      Source:European Journal of Medical Genetics, Volume 60, Issue 12
      Author(s): Gerarda Cappuccio, Marianna Alagia, Mariangela D'Anna, Carlotta Ranieri, Silvia Di Tommaso, Claudio Bruno, Chiara Fiorillo, Marina Pedemonte, Daria Loconte, Roberto Della Casa, Pietro Strisciuglio, Maria Isabella Ginocchio, Michele Pinelli, Nicoletta Resta, Nicola Brunetti-Pierri
      Post-zygotic activating mutations in PIK3CA and other genes encoding members of PI3K-AKT-mTOR pathway have been found in various overgrowth syndromes that have been grouped together as PIK3CA-related overgrowth spectrum (PROS). We report a female patient with gait disturbance, leg pain, isolated macrodactyly of the foot, and mild intellectual disability. Imaging of the lower limb showed a lipoblastoma of the right thigh. A mosaic gain-of-function mutation in the catalytic domain of PIK3CA (c.3140 A > G; p.His1047Arg) was detected in the adipose tissue and in skin cultured fibroblasts from the macrodactyly but not in blood. The leg pain and the severe walking disturbance improved slightly over time and serial MRI of the lower limbs suggested that the size of the lipoblastoma relative to the lower limb muscles or to the whole lower limb was unchanged as consequence of limb growth. This case report illustrates that pain and gait disturbance can be features of PROS and highlights the need of better knowledge about the natural history of the disease.

      PubDate: 2017-11-18T20:21:04Z
       
  • High bone mass due to novel LRP5 and AMER1 mutations
    • Abstract: Publication date: December 2017
      Source:European Journal of Medical Genetics, Volume 60, Issue 12
      Author(s): Alice Costantini, Päivi Kekäläinen, Riikka E. Mäkitie, Outi Mäkitie
      WNT signaling is a key regulator of bone metabolism and its increased or decreased activity leads to skeletal disorders. Here we describe two patients with high bone mass (HBM) caused by novel mutations in two different WNT pathway components. The first patient is a 53-year-old male with HBM. He was diagnosed at adult age based on significantly increased bone mineral density (BMD). He has undergone several surgeries due to excessive bone in ear canals, bilateral jaw exostoses and mandibular tori. Radiographs show severe cortical thickening of cranial and long bones. Sanger sequencing identified a novel heterozygous mutation c.592A>T (p.N198Y) in LRP5 (Low-density lipoprotein receptor-related protein 5). The second patient, an adolescent female, was diagnosed with skeletal dysplasia in early childhood. She had macrocephaly (head circumference +6.0 SD), facial dysmorphism, delayed motor development, laryngomalasia and epilepsy. Radiographic findings were consistent with osteopathia striata with cranial sclerosis. A novel heterozygous frameshift mutation c.655del (p.E219Rfs*63) in AMER1 (APC Membrane Recruiting Protein 1) was identified. Although both mutations are predicted to lead to increased WNT signaling with a consequent increase in bone formation, the resulting phenotypes are different; cranial sclerosis versus macrocephaly, long bone cortical thickening versus vertical striations and discordant neurological development. This report underscores the diversity of genotypes and phenotypes of HBM and facilitates their differential diagnosis.

      PubDate: 2017-11-18T20:21:04Z
       
  • Novel mosaic variants in two patients with Cornelia de Lange syndrome
    • Abstract: Publication date: Available online 15 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Jelena Pozojevic, Ilaria Parenti, Luitgard Graul-Neumann, Sara Ruiz Gil, Erwan Watrin, Kerstin S. Wendt, Ralf Werner, Tim M. Strom, Gabriele Gillessen-Kaesbach, Frank J. Kaiser
      Cornelia de Lange syndrome (CdLS) is a dominantly inherited developmental disorder caused by mutations in genes that encode for either structural (SMC1A, SMC3, RAD21) or regulatory (NIPBL, HDAC8) subunits of the cohesin complex. NIPBL represents the major gene of the syndrome and heterozygous mutations can be identified in more than 65% of patients. Interestingly, large portions of these variants were described as somatic mosaicism and often escape standard molecular diagnostics using lymphocyte DNA. Here we discuss the role of somatic mosaicism in CdLS and describe two additional patients with NIPBL mosaicism detected by targeted gene panel or exome sequencing. In order to verify the next generation sequencing data, Sanger sequencing or pyrosequencing on DNA extracted from different tissues were applied. None of the pathogenic variants was originally detected by Sanger sequencing on blood DNA. Patient 1 displays an unusual combination of clinical features: he is cognitively only mildly affected, but shows severe limb reduction defects. The second patient presents with a moderate phenotype. Interestingly, Sanger sequencing analysis on fibroblast DNA did not detect the disease-causing variant previously observed on the same DNA sample by exome sequencing. Subsequent analyses could confirm the variants by Sanger sequencing on buccal mucosa DNA. Notably, this is the first report of a higher mutational load in buccal mucosa than in fibroblast cells of a CdLS patient. Detection of low-level mosaicism is of utmost importance for an accurate molecular diagnosis and a proper genetic counseling of patients with a clinical diagnosis of CdLS. Next-generation sequencing technologies greatly facilitate the detection of low-level mosaicism, which might otherwise remain undetected by conventional sequencing approaches.

      PubDate: 2017-11-18T20:21:04Z
       
  • A rapid scoring tool to assess mutation probability in patients with
           inherited cardiac disorders
    • Abstract: Publication date: Available online 2 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Dominica Zentner, Tina Thompson, Jessica Taylor, Michael Bogwitz, Alison Trainer, Jitendra Vohra, Ingrid Winship, Paul A. James
      Aims To explore clinical features and relationship with positive mutation ascertainment in inherited heart diseases in order to develop a clinical tool to assist identification of individuals in whom to offer genetic testing. A clinical tool that increases pre test probability of mutation detection would have the benefits of improving patient counselling, prioritising cases for MPS and allowing equity in decision making. Methods and results Consecutive MPS mutation detection testing cases were identified (September 2014 - December 2015, n = 126). Cases were scored for the presence of pre-determined clinical and family history variables, blinded to MPS results. Subsequent unblinding allowed ascertainment of the odds ratio (OR) between these clinical variables and positive mutation detection. A clinical tool was developed and variables with higher OR association were given a higher weighting. The mean score in the cohort was 3.94: mutation positive subgroup 4.74, and mutation negative subgroup: 3.49 (t-test, p < 0.0001). The clinical tool was validated in a cohort of 40 patients. There was a strong linear correlation between increasing clinical tool score and probability of detecting a mutation (r2 = 0.88). Conclusion Clinical information on probands and their family history allows identification of individuals with a greater chance of positive mutation detection. This improves pre test counselling, allows equitable identification of individuals in whom to offer cardiac genetic testing and can be calibrated to a predictable ratio of positive mutation and missed opportunity cases for individual health services.

      PubDate: 2017-11-18T20:21:04Z
       
  • Genome-wide sequencing expands the phenotypic spectrum of EP300 variants
    • Abstract: Publication date: Available online 10 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Gregory Costain, Peter Kannu, Sarah Bowdin
      Many disease genes are defined by their role in causing specific clinically recognizable syndromes. Heterozygous loss of function of the gene EP300 is responsible for a minority of cases of Rubinstein-Taybi syndrome (RSTS). With the application of whole-exome sequencing and whole-genome sequencing, there is the potential to discover new genotype-phenotype correlations. The purpose of this case series is to describe three unrelated females without classic manifestations of RSTS who were unexpectedly found on genome-wide sequencing to have likely pathogenic variants in EP300. These individuals expand our knowledge of the disease spectrum by virtue of their very rare or novel clinical features, including hyperinsulinism. Results are placed within the context of all prior published EP300 cases not ascertained by targeted testing, which are disproportionately female compared with a cohort identified because of a clinical suspicion of RSTS (p = 0.01). There are implications for diagnosis, management, and genetic counselling of individuals with EP300-related disease.

      PubDate: 2017-11-11T18:47:53Z
       
  • Homozygous loss of function BRCA1 variant causing a fanconi-anemia-like
           phenotype, a clinical report and review of previous patients
    • Abstract: Publication date: Available online 10 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Bruna L. Freire, Thais K. Homma, Mariana F.A. Funari, Antônio M. Lerario, Aline de Medeiros Leal, Elvira D. Rodrigues Pereira Velloso, Alexsandra C. Malaquias, Alexander A.L. Jorge
      Background Fanconi Anemia (FA) is a rare and heterogeneous genetic syndrome. It is associated with short stature, bone marrow failure, high predisposition to cancer, microcephaly and congenital malformation. Many genes have been associated with FA. Previously, two adult patients with biallelic pathogenic variant in Breast Cancer 1 gene (BRCA1) had been identified in Fanconi Anemia-like condition. Clinical report The proband was a 2.5 year-old girl with severe short stature, microcephaly, neurodevelopmental delay, congenital heart disease and dysmorphic features. Her parents were third degree cousins. Routine screening tests for short stature was normal. Methods We conducted whole exome sequencing (WES) of the proband and used an analysis pipeline to identify rare nonsynonymous genetic variants that cause short stature. Results We identified a homozygous loss-of-function BRCA1 mutation (c.2709T > A; p. Cys903*), which promotes the loss of critical domains of the protein. Cytogenetic study with DEB showed an increased chromosomal breakage. We screened heterozygous parents of the index case for cancer and we detected, in her mother, a metastatic adenocarcinoma in an axillar lymph node with probable primary site in the breast. Conclusion It is possible to consolidate the FA-like phenotype associated with biallelic loss-of-function BRCA1, characterized by microcephaly, short stature, developmental delay, dysmorphic face features and cancer predisposition. In our case, the WES allowed to establish the genetic cause of short stature in the context of a chromosome instability syndrome. An identification of BRCA1 mutations in our patient allowed precise genetic counseling and also triggered cancer screening for the patient and her family members.

      PubDate: 2017-11-11T18:47:53Z
       
  • Familial early-onset deep venous thrombosis associated with a novel HRG
           mutation
    • Abstract: Publication date: Available online 3 November 2017
      Source:European Journal of Medical Genetics
      Author(s): Junfu Luo, Wenwen Zhang, Qingfu Zeng, Weimin Zhou, Qing Cao, Wei Zhou
      Deep venous thrombosis (DVT) remains a serious clinical problem that affects millions of people worldwide. Some DVT cases are caused by inherited thrombophilia derived from genetic aberrations and several disease-causing genes have been identified so far. Among them, HRG is an uncommon one with limited related reports. Here, we reported on a family with early-onset DVT where acquired risky conditions were excluded. Whole exome sequencing revealed a novel heterozygous single base pair substitution in exon 2 of HRG gene resulting in a conserved residue replacement of the protein (c. C271T, p. P73S). Sanger sequencing confirmed the co-segregation of the mutation and plasma quantification determined circulating protein deficiency. The mutation might therefore impair hemostatic balance by causing reduced circulating HRG level. Our study broadens the mutation spectrum of the HRG gene and underscores the importance of its function in regulating coagulation pathway.

      PubDate: 2017-11-11T18:47:53Z
       
  • The spectrum of Familial Mediterranean Fever gene (MEFV) mutations and
           genotypes in Iran, and report of a novel missense variant (R204H)
    • Abstract: Publication date: Available online 21 September 2017
      Source:European Journal of Medical Genetics
      Author(s): Nader Ebadi, Abbas Shakoori, Masoumeh Razipour, Arash Salmaninejad, Razieh Zarifian Yeganeh, Saman Mehrabi, Seyed RezaRaees Karami, Malihea Khaleghian, Hamidreza Azhideh
      Background Familial Mediterranean Fever (FMF) is an autosomal recessive disorder, characterized by recurrent and self-limited episodes of fever, abdominal pain, synovitis and pleuritis. FMF as the most common inherited monogenic autoinflammatory disease mainly affects ethnic groups of the Mediterranean basin, Arab, Jewish, Turkish, Armenian North Africans and Arabic descent. Materials and methods In the present study, we selected 390 unrelated FMF patients according to the Tel-Hashomer criteria, and analyzed all patients for 12 most common mutations of MEFV gene by reverse hybridization assay (FMF strip assay). We also investigated exon 2 and 10 of MEFV gene in 78 patients by Sanger sequencing. Results According to strip assay results, at least one mutation was found in 234 patients (60%), and no mutation was found in other 156 patients (40%). The five most common mutations and allelic frequencies were M694V (13.6%), E148Q (10.4%), M694I (6.5%), V726A (4.1%), and M680I (3.8%). Moreover, we detected a novel missense variant (R204H, c.611 G > A) (SCV000297822) and following rare mutations among sequenced samples; R202Q, P115T, G304R, and E230K. Conclusion This study describes the MEFV mutations spectrum and distribution in Iranian population, and shows different mutation patterns among Iranian ethnicities. Moreover, M694V is the most common MEFV mutation in Iran.

      PubDate: 2017-09-24T00:25:15Z
       
  • A chinese boy with geleophysic dysplasia caused by compound heterozygous
           mutations in ADAMTSL2
    • Abstract: Publication date: Available online 14 September 2017
      Source:European Journal of Medical Genetics
      Author(s): Li Dongxiao, Dong Hui, Zheng Hong, Song Jinqing, Li Xiyuan, Jin Ying, Liu Yupeng, Yang Yanling
      Geleophysic dysplasia, belonging to the group of acromelic dysplasia, is a rare genetic disease. Two genes, FBN1 and ADAMTSL2, were known to be linked to this disorder. The disorder presents as extreme short stature, short limbs, small hands and feet, stubby fingers and toes, joint stiffness, toe walking, skin thickening, progressive cardiac valvular thickening and characteristic facial features, including a round face with full cheeks. Here, we report the first Chinese case with geleophysic dysplasia type 1 based on clinical and genetic features. The boy was admitted because of severe physical growth retardation and mild motor retardation. Comprehensive medical evaluations were performed including metabolic studies, endocrine function examination, bone X-rays and echocardiography. Much delayed bone age and geleophysic dysplasia were found. Targeted next-generation sequencing was used to detect genetic mutations associated with skeletal dysplasia. Sanger sequencing was used to confirm the mutations in the patient. PCR amplification, cloing, and sequencing was used to determine the de novo mutation origin. Two compound heterozygous mutations were confirmed in the ADAMTSL2 gene of the patient. The c.340G > A (p.Glu114Lys) mutation was a de novo heterozygous mutation, and our results suggested that it was located on the paternal allele. While the c.234-2A > G inherited from his mother was a novel pathogenic heterozygous splicing mutation. Growth hormone deficiency had been observed in the patient. His growth velocity was improved by growth hormone supplementation. In conclusion, we have identified a novel splicing mutation of ADAMTSL2 carried by a Chinese boy with geleophysic dysplasia type 1. The patient was treated effectively with growth hormone supplementation.

      PubDate: 2017-09-18T00:08:51Z
       
  • Al-Awadi-Raas-Rothschild syndrome with dental anomalies and a novel WNT7A
           mutation
    • Abstract: Publication date: Available online 14 September 2017
      Source:European Journal of Medical Genetics
      Author(s): Piranit Nik Kantaputra, Seema Kapoor, Prashant Verma, Massupa Kaewgahya, Katsushige Kawasaki, Atsushi Ohazama, James R. Ketudat Cairns
      Al-Awadi-Raas-Rothschild syndrome (AARRS; OMIM 276820) is a very rare autosomal recessive limb malformation syndrome caused by WNT7A mutations. AARRS is characterized by various degrees of limb aplasia and hypoplasia. Normal intelligence and malformations of urogenital system are frequent findings. Complete loss of WNT7A function has been shown to cause AARRS, however, its partial loss leads to the milder malformation, Fuhrmann syndrome. An Indian boy affected with AARRS is reported. A novel homozygous base substitution mutation c.550A > C (p.Asn184Asp) is identified in the patient. Parents were heterozygous for the mutation. In addition to the typical features of AARRS, the patient had agenesis of the mandibular left deciduous lateral incisor. The heterozygous parents had microdontia of the maxillary left permanent third molar and taurodontism (enlarged dental pulp chamber at the expense of root) in a number of their permanent molars. Whole exome sequencing of the patient and his parents ruled out mutations in 11 known hypodontia-associated genes including WNT10A, MSX1, EDA, EDAR, EDARADD, PAX9, AXIN2, GREM2, NEMO, KRT17, and TFAP2B. In situ hybridization during tooth development showed Wnt7a expression in wild-type tooth epithelium at E14.5. All lines of evidence suggest that WNT7A has important role in tooth development and its mutation may lead to tooth agenesis, microdontia, and taurodontism. Oral examination of patients with AARRS and Fuhrmann syndromes is highly recommended.

      PubDate: 2017-09-18T00:08:51Z
       
  • A homozygote TREX1 mutation in two siblings with different phenotypes:
           Chilblains and cerebral vasculitis
    • Abstract: Publication date: Available online 13 September 2017
      Source:European Journal of Medical Genetics
      Author(s): Rabia Miray Kisla Ekinci, Sibel Balci, Atil Bisgin, Derya Ufuk Altintas, Mustafa Yılmaz
      Three prime repair exonuclease 1 degrades single and double stranded DNA with 3′-5′ nuclease activity and its mutations are related to type 1 IFN mediated autoinflammation due to accumulated intracellular nucleic acids. To date, several cases of systemic lupus erythematosus, Aicardi-Goutieres syndrome, familial chilblain lupus, retinal vasculopathy-cerebral leukodystrophy have been reported with TREX1 mutations. Chilblain lupus is a skin disease characterized by blue-reddish coloring, swelling or ulcers on acral regions of body such as fingertips, heels, nose and auricles. Central nervous system vasculitis is a prominent cause of childhood strokes. 10 families with familial chilblain lupus related to TREX1 mutations were reported previously in the literature, in which homozygote D18N variant in TREX1 gene was related to chilblains with cerebral vasculitis. In this report, whole-exome-sequencing revealed a homozygote R114C mutation in TREX1 gene was shown in two siblings with recurrent chilblains whom one of them was the second case accompanied by cerebral vasculitis in the literature. As a result, the approach of WES in clinical use revealed a novel mutation in clinically heterogenous patients to provide genetic counseling.

      PubDate: 2017-09-18T00:08:51Z
       
  • Exome sequencing for the differential diagnosis of ciliary
           chondrodysplasias: Example of a WDR35 mutation case and review of the
           literature
    • Abstract: Publication date: Available online 12 September 2017
      Source:European Journal of Medical Genetics
      Author(s): Dinu Antony, Narayanan Nampoory, Chiara Bacchelli, Motasem Melhem, Kaman Wu, Chela T. James, Philip L. Beales, Mike Hubank, Daisy Thomas, Anant Mashankar, Kazem Behbehani, Miriam Schmidts, Osama Alsmadi
      Exome sequencing is becoming widely popular and affordable, making it one of the most desirable methods for the identification of rare genetic variants for clinical diagnosis. Here, we report the clinical application of whole exome sequencing for the ultimate diagnosis of a ciliary chondrodysplasia case presented with an initial clinical diagnosis of Asphyxiating Thoracic Dystrophy (ATD, Jeune Syndrome). We have identified a novel homozygous missense mutation in WDR35 (c.206G > A), a gene previously associated with Sensenbrenner Syndrome, Ellis-van Creveld syndrome and Short-rib polydactyly syndrome type V. The genetic findings in this family led to the re-evaluation of the initial diagnosis and a differential diagnosis of Sensenbrenner Syndrome was made after cautious re-examination of the patient. Cell culture studies revealed normal subcellular localization of the mutant WDR35 protein in comparison to wildtype protein, pointing towards impaired protein-protein interaction and/or altered cell signaling pathways as a consequence of the mutated allele. This research study highlights the importance of including pathogenic variant identification in the diagnosis pipeline of ciliary chondrodysplasias, especially for clinically not fully defined phenotypes.

      PubDate: 2017-09-18T00:08:51Z
       
  • Case report: Left ventricular noncompaction cardiomyopathy and RASopathies
    • Abstract: Publication date: Available online 12 September 2017
      Source:European Journal of Medical Genetics
      Author(s): John Lynn Jefferies, Carlos Enrique Prada, Juli Ann Sublett
      The following is a case report of 6 patients with Noonan syndrome (NS) and/or a related RASsopathy that also have evidence of left ventricular noncompaction cardiomyopathy (LVNC). Noonan syndrome,a type of RASopathy, is an autosomal dominant disorder that is typically associated with congenital heart defects and hypertrophic cardiomyopathy. There have been minimal reports of Noonan syndrome or other RASopathy and the association of LVNC. This report promulgates 6 nonrelated cases of Noonan syndrome or unspecified RASopathy and LVNC.

      PubDate: 2017-09-18T00:08:51Z
       
  • A structured assessment of motor function, behavior, and communication in
           patients with Wolf–Hirschhorn syndrome
    • Abstract: Publication date: Available online 14 August 2017
      Source:European Journal of Medical Genetics
      Author(s): Heidi E. Nag, David K. Bergsaker, Bente S. Hunn, Susanne Schmidt, Lise B. Hoxmark
      The present study aimed to increase the knowledge about Wolf–Hirschhorn syndrome (WHS), especially concerning motor function, autism spectrum disorders (ASD), and adapted behavior, but also regarding clinical symptoms in general. Motor function was evaluated via systematic observation. Standardized assessments such as the Vineland Adapted Behavior Scales II (VABS II), the Social Communication Questionnaire (SCQ), and the Child Behavior Checklist (CBCL) or Adult Behavior Checklist (ABCL) were used for the behavioral assessment. In total, two males and eight females between one and 48 years of age with a genetically confirmed diagnosis of WHS and their parents participated in this study. Deletion sizes were known for seven of the ten patients and varied between 55 Kb and 20 Mb. The chromosome coordinates were known for six of them, and none of those had the same break points in their deletion. The main finding in this study was that patients with WHS may have a better outcome regarding motor skills and expressive communication than previously described. We could confirm the main medical findings described earlier, but found also a population with a less severe dysmorphology, fewer congenital malformations, and fewer medical challenges than expected. Sleep problems may persist into adulthood and need a more thorough investigation. Research on possible indications of ASD is strongly needed for targeted interventions. In conclusion, a more thorough assessment of communication, possible ASD, and sleep in larger groups of patients with WHS are needed to confirm and further investigate the findings from this study and to provide more targeted interventions for WHS patients.

      PubDate: 2017-08-26T20:07:13Z
       
  • Early fetal presentation of Koolen-de Vries: Case report with literature
           review
    • Abstract: Publication date: Available online 12 August 2017
      Source:European Journal of Medical Genetics
      Author(s): Fanny Sauvestre, Florent Marguet, Caroline Rooryck, Marie-Laure Vuillaume, Frédéric Cardinaud, Annie Laquerrière, Gwenaëlle André, Fanny Pelluard
      Koolen-de Vries syndrome (MIM#610443) is a rare microdeletion syndrome involving the 17q21.31 region, which was first described by Koolen in 2006. Clinical and behavioral characteristics have been extensively reported from more than 100 postnatal cases including infants, children and young adults. The syndrome is highly clinically heterogeneous, but the main features associate characteristic cranio-facial dysmorphism, heart defects, limb, skeletal, genito-urinary anomalies, along with intellectual disability with early childhood epilepsy and behavioral disturbances. Central nervous system malformations usually consist in hydrocephalus and thin corpus callosum. We report herein an early fetal case with an apparently isolated abnormal corpus callosum diagnosed by ultrasonography, for which a medical termination of the pregnancy was achieved at 22 weeks of gestation. Postmortem examination displayed facial dysmorphism consisting of hypertelorism, short philtrum and flat and broad nose, cleft palate and left duplex ureter. Neuropathological examination revealed a mega corpus callosum that has never been reported so far in this syndrome. Array-CGH performed on thymic DNA tissue revealed a 17q21.31 microdeletion, which allowed for the confirmation of early occurring Koolen-de Vries syndrome.

      PubDate: 2017-08-26T20:07:13Z
       
  • Familial 1p36.3 microduplication resulting from a 1p-9q non-reciprocal
           translocation
    • Abstract: Publication date: Available online 12 August 2017
      Source:European Journal of Medical Genetics
      Author(s): Valentine Marquet, Sylvie Bourthoumieu, Amelia Dobrescu, Cécile Laroche-Raynaud, Catherine Yardin
      Unlike the 1p36 microdeletion syndrome, which has been extensively described, 1p36 microduplications have rarely been reported. We describe a three years old boy presenting with a severe global developmental delay and a few dysmorphic features. Cytogenetic analyses revealed a maternally inherited 3.35 Mb microduplication of chromosomal band 1p36.3. The maternal grand-father is also carrier of the same chromosomal rearrangement. Interestingly, the duplicated 1p36.3 segment was found to be localized at the telomeric end of the long arms of a chromosome 9, probably deriving from a 1p36.3-9qter non-reciprocal translocation. This particular type of chromosomal translocation has rarely been reported, and its mechanism is unclear. The phenotypical features associated with 1p36.3 microduplication vary due to the non-recurrent breakpoints of the rearrangements in this particular region. However, when compiling the few described cases, the phenotypical spectrum seems to include mainly developmental delay, mild facial dysmorphism, and neurological, cardiac and skeletal anomalies. The description of new patients carrying a 1p36.3 duplication like ours will lead to further delineation of the phenotypical spectrum and may help to find critical regions and causative genes implicated in the phenotype.

      PubDate: 2017-08-26T20:07:13Z
       
  • BRCA1/2 missense mutations and the value of in-silico analyses
    • Abstract: Publication date: Available online 12 August 2017
      Source:European Journal of Medical Genetics
      Author(s): Carolin E. Sadowski, Daniela Kohlstedt, Cornelia Meisel, Katja Keller, Kerstin Becker, Luisa Mackenroth, Andreas Rump, Evelin Schröck, Pauline Wimberger, Karin Kast
      Introduction The clinical implications of genetic variants in BRCA1/2 in healthy and affected individuals are considerable. Variant interpretation, however, is especially challenging for missense variants. The majority of them are classified as variants of unknown clinical significance (VUS). Computational (in-silico) predictive programs are easy to access, but represent only one tool out of a wide range of complemental approaches to classify VUS. With this single-center study, we aimed to evaluate the impact of in-silico analyses in a spectrum of different BRCA1/2 missense variants. Methods We conducted mutation analysis of BRCA1/2 in 523 index patients with suspected hereditary breast and ovarian cancer (HBOC). Classification of the genetic variants was performed according to the German Consortium (GC)-HBOC database. Additionally, all missense variants were classified by the following three in-silico prediction tools: SIFT, Mutation Taster (MT2) and PolyPhen2 (PPH2). Results Overall 201 different variants, 68 of which constituted missense variants were ranked as pathogenic, neutral, or unknown. The classification of missense variants by in-silico tools resulted in a higher amount of pathogenic mutations (25% vs. 13.2%) compared to the GC-HBOC-classification. Altogether, more than fifty percent (38/68, 55.9%) of missense variants were ranked differently. Sensitivity of in-silico-tools for mutation prediction was 88.9% (PPH2), 100% (SIFT) and 100% (MT2). Conclusion We found a relevant discrepancy in variant classification by using in-silico prediction tools, resulting in potential overestimation and/or underestimation of cancer risk. More reliable, notably gene-specific, prediction tools and functional tests are needed to improve clinical counseling.

      PubDate: 2017-08-15T17:24:44Z
       
  • Impairment of different protein domains causes variable clinical
           presentation within Pitt-Hopkins syndrome and suggests intragenic
           molecular syndromology of TCF4
    • Abstract: Publication date: Available online 12 August 2017
      Source:European Journal of Medical Genetics
      Author(s): Maria Francesca Bedeschi, Giuseppe Marangi, Maria Rosaria Calvello, Stefania Ricciardi, Francesca Pia Chiara Leone, Marco Baccarin, Silvana Guerneri, Daniela Orteschi, Marina Murdolo, Serena Lattante, Silvia Frangella, Beth Keena, Margaret H. Harr, Elaine Zackai, Marcella Zollino
      Pitt-Hopkins syndrome is a neurodevelopmental disorder characterized by severe intellectual disability and a distinctive facial gestalt. It is caused by haploinsufficiency of the TCF4 gene. The TCF4 protein has different functional domains, with the NLS (nuclear localization signal) domain coded by exons 7–8 and the bHLH (basic Helix-Loop-Helix) domain coded by exon 18. Several alternatively spliced TCF4 variants have been described, allowing for translation of variable protein isoforms. Typical PTHS patients have impairment of at least the bHLH domain. To which extent impairment of the remaining domains contributes to the final phenotype is not clear. There is recent evidence that certain loss-of-function variants disrupting TCF4 are associated with mild ID, but not with typical PTHS. We describe a frameshift-causing partial gene deletion encompassing exons 4–6 of TCF4 in an adult patient with mild ID and nonspecific facial dysmorphisms but without the typical features of PTHS, and a c.520C > T nonsense variant within exon 8 in a child presenting with a severe phenotype largely mimicking PTHS, but lacking the typical facial dysmorphism. Investigation on mRNA, along with literature review, led us to suggest a preliminary phenotypic map of loss-of-function variants affecting TCF4. An intragenic phenotypic map of loss-of-function variants in TCF4 is suggested here for the first time: variants within exons 1–4 and exons 4–6 give rise to a recurrent phenotype with mild ID not in the spectrum of Pitt-Hopkins syndrome (biallelic preservation of both the NLS and bHLH domains); variants within exons 7–8 cause a severe phenotype resembling PTHS but in absence of the typical facial dysmorphism (impairment limited to the NLS domain); variants within exons 9–19 cause typical Pitt-Hopkins syndrome (impairment of at least the bHLH domain). Understanding the TCF4 molecular syndromology can allow for proper nosology in the current era of whole genomic investigations.

      PubDate: 2017-08-15T17:24:44Z
       
  • Reducing diagnostic turnaround times of exome sequencing for families
           requiring timely diagnoses
    • Abstract: Publication date: Available online 12 August 2017
      Source:European Journal of Medical Genetics
      Author(s): Aurélie Bourchany, Christel Thauvin-Robinet, Daphné Lehalle, Ange-Line Bruel, Alice Masurel-Paulet, Nolwenn Jean, Sophie Nambot, Marjorie Willems, Laetitia Lambert, Salima El Chehadeh-Djebbar, Elise Schaefer, Aurélia Jaquette, Judith St-Onge, Charlotte Poe, Thibaud Jouan, Martin Chevarin, Patrick Callier, Anne-Laure Mosca-Boidron, Nicole Laurent, Mathilde Lefebvre, Frédéric Huet, Nada Houcinat, Sébastien Moutton, Christophe Philippe, Frédéric Tran-Mau-Them, Antonio Vitobello, Paul Kuentz, Yannis Duffourd, Jean-Baptiste Rivière, Julien Thevenon, Laurence Faivre
      Background and objective Whole-exome sequencing (WES) has now entered medical practice with powerful applications in the diagnosis of rare Mendelian disorders. Although the usefulness and cost-effectiveness of WES have been widely demonstrated, it is essential to reduce the diagnostic turnaround time to make WES a first-line procedure. Since 2011, the automation of laboratory procedures and advances in sequencing chemistry have made it possible to carry out diagnostic whole genome sequencing from the blood sample to molecular diagnosis of suspected genetic disorders within 50 h. Taking advantage of these advances, the main objective of the study was to improve turnaround times for sequencing results. Methods WES was proposed to 29 patients with severe undiagnosed disorders with developmental abnormalities and faced with medical situations requiring rapid diagnosis. Each family gave consent. The extracted DNA was sequenced on a NextSeq500 (Illumina) instrument. Data were analyzed following standard procedures. Variants were interpreted using in-house software. Each rare variant affecting protein sequences with clinical relevance was tested for familial segregation. Results The diagnostic rate was 45% (13/29), with a mean turnaround time of 40 days from reception of the specimen to delivery of results to the referring physician. Besides permitting genetic counseling, the rapid diagnosis for positive families led to two pre-natal diagnoses and two inclusions in clinical trials. Conclusions This pilot study demonstrated the feasibility of rapid diagnostic WES in our primary genetics center. It reduced the diagnostic odyssey and helped provide support to families.

      PubDate: 2017-08-15T17:24:44Z
       
  • A novel mutation in SMOC1 and variable phenotypic expression in two
           patients with Waardenburg anophthalmia syndrome
    • Abstract: Publication date: Available online 12 August 2017
      Source:European Journal of Medical Genetics
      Author(s): Javad Jamshidi, Shokoufeh Abdollahi, Hamid Ghaedi, Elham Alehabib, Abbas Tafakhori, Somayeh Alinaghi, Marjan Chapi, Amir Hossein Johari, Hossein Darvish
      Waardenburg anophthalmia syndrome (WAS) is a rare disorder that mostly affects the eyes and distal limbs. In the current study we reported two Iranian patients with WAS. The first case was a 26-year-old girl with unilateral anophthalmia, bilateral camptodactyly and clinodactyly in her hands, oligodactly in her left foot and syndactyly of the second to fifth toes in her right foot. She also had severe hearing loss in both ears. The second case was a 12-year-old boy with bilateral anophthalmia, camptodactyly in his right hand, oligodactyly in his foot, clubfoot, and cryptorchidism. Both patients were mentally normal. To detect the causative mutation all exons and exon-intron boundaries of SMOC1 gene were sequenced in patients and other normal family members. We found a homozygous missense mutation (NM_001034852.2(SMOC1):c.367T > C) in exon 3 of SMOC1 gene in both patients. As the mutation segregated with the disease in the family, it should be the causative mutation. Our study extended the mutation spectrum of SMOC1 gene related to WAS.

      PubDate: 2017-08-15T17:24:44Z
       
  • Prenatal diagnosis of complex phenotype in a 13-week-old fetus with an
           
    • Abstract: Publication date: Available online 12 August 2017
      Source:European Journal of Medical Genetics
      Author(s): Feodora Stipoljev, Danka Miric-Tesanic, Tomislav Hafner, Maja Barbalic, Monika Logara, Ruzica Lasan-Trcic, Ana Vicic, Romana Gjergja-Juraski
      We report the first trimester three-dimensional ultrasonographic findings in a 13-week-old fetus with complex phenotype and a de novo 4.7 Mb multigene deletion encompassing chromosome region 20q13.13-q13.2 detected by chromosomal microarray. Fetal sonography detected radial-ray anomalies in the form of bilateral absence of thumbs and the left club hand deformity. The presence of single atrioventricular canal instead of the atrial septal defect typical for Holt-Oram syndrome pointed us to rather suspect the SALL4 related diseases. Central nervous system anomaly in the form of enlarged lateral brain ventricles with choroid plexus shifted backwards was not previously reported as a part of SALL4 related disorders. The pregnancy was terminated at 14 + 3 weeks of pregnancy and the autopsy confirmed ultrasonographic findings. Deleted region included 38 genes, where only SALL4, ADNP and KCNB1 heterozygote pathogenic variants were described to because of syndromic forms. Radial ray anomalies are common part of clinical picture of SALL4 related disorders. Despite the lack of prenatally described cases, we hypothesized that maldevelopment of lateral brain ventriculomegaly could be very early sonographic sign of disturbed ADNP expression causing Helsmoortel-Van der Aa syndrome, but in some extent also of KCNB1 related early-onset epileptic encephalopathy. Furthermore, the possible dosage-dependent influence of recessive genes located in this region cannot be also excluded. The use of genome-wide technologies enables the detection of subtle chromosomal imbalances and more precise familial genetic counseling regarding actual and future pregnancies.

      PubDate: 2017-08-15T17:24:44Z
       
 
 
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