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Saint-André-lez-Lille, France

Jones W.D.,University of London | Dafou D.,Kings College London | McEntagart M.,University of London | Woollard W.J.,Kings College London | And 9 more authors.
American Journal of Human Genetics | Year: 2012

Excessive growth of terminal hair around the elbows (hypertrichosis cubiti) has been reported both in isolation and in association with a variable spectrum of associated phenotypic features. We identified a cohort of six individuals with hypertrichosis cubiti associated with short stature, intellectual disability, and a distinctive facial appearance, consistent with a diagnosis of Wiedemann-Steiner syndrome (WSS). Utilizing a whole-exome sequencing approach, we identified de novo mutations in MLL in five of the six individuals. MLL encodes a histone methyltransferase that regulates chromatin-mediated transcription through the catalysis of methylation of histone H3K4. Each of the five mutations is predicted to result in premature termination of the protein product. Furthermore, we demonstrate that transcripts arising from the mutant alleles are subject to nonsense-mediated decay. These findings define the genetic basis of WSS, provide additional evidence for the role of haploinsufficency of histone-modification enzymes in multiple-congenital-anomaly syndromes, and further illustrate the importance of the regulation of histone modification in development. © 2012 The American Society of Human Genetics.

Petit F.,Service de Genetique Clinique | Petit F.,University of Lille Nord de France | Plessis G.,Caen University Hospital Center | Decamp M.,Laboratoire Of Genetique Medicale | And 4 more authors.
European Journal of Medical Genetics | Year: 2015

Here we report three patients affected with neurodevelopmental disorders and harbouring 21q21 deletions involving NCAM2 gene. NCAM (Neural Cell Adhesion Molecule) proteins are involved in axonal migration, synaptic formation and plasticity. Poor axonal growth and fasciculation is observed in animal models deficient for NCAM2. Moreover, this gene has been proposed as a candidate for autism, based on genome-wide association studies. In this report, we provide a comprehensive molecular and phenotypical characterisation of three deletion cases giving additional clues for the involvement of NCAM2 in neurodevelopment. © 2014 Elsevier Masson SAS.

Rieder M.J.,University of Washington | Green G.E.,University of Michigan | Park S.S.,Seattle Childrens Research Institute | Stamper B.D.,Seattle Childrens Research Institute | And 22 more authors.
American Journal of Human Genetics | Year: 2012

Auriculocondylar syndrome (ACS) is a rare, autosomal-dominant craniofacial malformation syndrome characterized by variable micrognathia, temporomandibular joint ankylosis, cleft palate, and a characteristic "question-mark" ear malformation. Careful phenotypic characterization of severely affected probands in our cohort suggested the presence of a mandibular patterning defect resulting in a maxillary phenotype (i.e., homeotic transformation). We used exome sequencing of five probands and identified two novel (exclusive to the patient and/or family studied) missense mutations in PLCB4 and a shared mutation in GNAI3 in two unrelated probands. In confirmatory studies, three additional novel PLCB4 mutations were found in multigenerational ACS pedigrees. All mutations were confirmed by Sanger sequencing, were not present in more than 10,000 control chromosomes, and resulted in amino-acid substitutions located in highly conserved protein domains. Additionally, protein-structure modeling demonstrated that all ACS substitutions disrupt the catalytic sites of PLCB4 and GNAI3. We suggest that PLCB4 and GNAI3 are core signaling molecules of the endothelin-1-distal-less homeobox 5 and 6 (EDN1-DLX5/DLX6) pathway. Functional studies demonstrated a significant reduction in downstream DLX5 and DLX6 expression in ACS cases in assays using cultured osteoblasts from probands and controls. These results support the role of the previously implicated EDN1-DLX5/6 pathway in regulating mandibular specification in other species, which, when disrupted, results in a maxillary phenotype. This work defines the molecular basis of ACS as a homeotic transformation (mandible to maxilla) in humans. © 2012 by The American Society of Human Genetics. All rights reserved.

De Pontual L.,University of Paris Descartes | De Pontual L.,University of Paris 13 | Yao E.,Sloan Kettering Cancer Center | Callier P.,Service de Genetique | And 15 more authors.
Nature Genetics | Year: 2011

MicroRNAs (miRNAs) are key regulators of gene expression in animals and plants. Studies in a variety of model organisms show that miRNAs modulate developmental processes. To our knowledge, the only hereditary condition known to be caused by a miRNA is a form of adult-onset non-syndromic deafness, and no miRNA mutation has yet been found to be responsible for any developmental defect in humans. Here we report the identification of germline hemizygous deletions of MIR17HG, encoding the miR-17∼92 polycistronic miRNA cluster, in individuals with microcephaly, short stature and digital abnormalities. We demonstrate that haploinsufficiency of miR-17∼92 is responsible for these developmental abnormalities by showing that mice harboring targeted deletion of the miR-17∼92 cluster phenocopy several key features of the affected humans. These findings identify a regulatory function for miR-17∼92 in growth and skeletal development and represent the first example of an miRNA gene responsible for a syndromic developmental defect in humans. © 2011 Nature America, Inc. All rights reserved.

Simpson M.A.,Kings College London | Irving M.D.,Kings College London | Asilmaz E.,Kings College London | Gray M.J.,The New School | And 15 more authors.
Nature Genetics | Year: 2011

We used an exome-sequencing strategy and identified an allelic series of NOTCH2 mutations in Hajdu-Cheney syndrome, an autosomal dominant multisystem disorder characterized by severe and progressive bone loss. The Hajdu-Cheney syndrome mutations are predicted to lead to the premature truncation of NOTCH2 with either disruption or loss of the C-terminal proline-glutamate-serine- threonine-rich proteolytic recognition sequence, the absence of which has previously been shown to increase Notch signaling. © 2011 Nature America, Inc. All rights reserved.

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