De Novo SOX6 Variants Cause a Neurodevelopmental Syndrome Associated with ADHD, Craniosynostosis, and Osteochondromas

Introduction: The SOX gene family consists of twenty transcription factors that play a pivotal role in cell fate and differentiation during the development of many organ systems. Within these SRY-related (SOX) genes is a highly conserved high mobility group (HMG) domain that has been shown to be critical for DNA binding and bending, nuclear trafficking, and protein-protein interactions. Mutations within this transcription factor family have been associated with rare congenital disorders, known as SOXopathies. These mutations are commonly de novo, heterozygous and inactivating, and exhibit gene haploinsufficiency. Of these twenty transcription factors, SOX6 is known to be involved in chondrocyte differentiation and development of the central nervous system. Although there have been reports of SOX6 variants causing adult pathological conditions, there has yet to be a well-established association between SOX6 variants and a developmental syndrome. Objectives: The objective of this study was to use clinical and genetic data to examine SOX6 mutations found in 19 individuals demonstrating developmental delay and to test the transcriptional activity of the 4 missense variants in vitro to determine if SOX6 haploinsufficiency leads to a neurodevelopmental SOXopathy. Methods: Nineteen individuals were identified as carriers of SOX6 variants, confirmed by molecular karyotyping, whole-exome sequencing, or whole-genome sequencing. Clinical pathogenicity was predicted and assessed in silico and in vitro. Expression plasmids for SOX6 missense variants were generated by PCR mutagenesis. The four missense variants generated were: p.Trp161Cys, p.Met605Thr, p.Trp639Arg, and p.Ser746Leu, with p.Met605Thr and p.Trp639Arg located within the HMG domain. For reporter assays, HEK293 cells were transfected in triplicate cultures with 3.5 µL ViaFect Transfection Reagent and a total of 1000ng of DNA. SOX6 intracellular localization was tested by transfecting either HEK293 or COS-1 cells and cytoplasmic and nuclear extracts were prepared for Western Blot analysis. Whole cell extracts transfected with respective WT-SOX6 or variant plasmid were also prepared for a dimerization assay. SOX6’s ability to bind DNA was also tested in an electrophoretic mobility shift assay (EMSA). Results: Study cohort consisted of 19 individuals from 17 unrelated families originating in Belgium, Canada, France, Germany, the Netherlands, Slovenia, the UK, and the US. These individuals shared milestone delays and intellectual disability, and exhibited abnormalities including mild dysmorphism, craniosynostosis, and osteochondromas. Immunoblots of nuclear and cytoplasmic extracts showed all variants were efficiently expressed however p.Met605Thr and p.Trp639Arg were not translocated or retained into the nucleus as efficiently as WT-SOX6 and the other two missense variants. The EMSA showed that proteins outside of the HMG domain behaved like WT-SOX6, but p.Met605Thr and p.Trp639Arg failed to bind the DNA probe. Reporter assay activity showed that the two variants outside of the HMG domain p.Trp161Cys and p.Ser746Leu displayed similar or slightly higher activity compared to WT-SOX6 while the two variants p.Met605Thr and p.Trp639Arg showed diminished reporter activity. Conclusions: These findings provide evidence that SOX6 variants cause a SOXopathy, which has been designated in Online Mendelian Inheritance in Man (OMIM) as #618971 Tolchin-Le Caignec syndrome (TOLCAS)

Utero-vaginal aplasia (Mayer-Rokitansky-Küster-Hauser syndrome) associated with deletions in known DiGeorge or DiGeorge-like loci

<p>Abstract</p> <p>Background</p> <p>Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is characterized by congenital aplasia of the uterus and the upper part of the vagina in women showing normal development of secondary sexual characteristics and a normal 46, XX karyotype. The uterovaginal aplasia is either isolated (type I) or more frequently associated with other malformations (type II or Müllerian Renal Cervico-thoracic Somite (MURCS) association), some of which belong to the malformation spectrum of DiGeorge phenotype (DGS). Its etiology remains poorly understood. Thus the phenotypic manifestations of MRKH and DGS overlap suggesting a possible genetic link. This would potentially have clinical consequences.</p> <p>Methods</p> <p>We searched DiGeorge critical chromosomal regions for chromosomal anomalies in a cohort of 57 subjects with uterovaginal aplasia (55 women and 2 aborted fetuses). For this candidate locus approach, we used a multiplex ligation-dependent probe amplification (MLPA) assay based on a kit designed for investigation of the chromosomal regions known to be involved in DGS.</p> <p>The deletions detected were validated by Duplex PCR/liquid chromatography (DP/LC) and/or array-CGH analysis.</p> <p>Results</p> <p>We found deletions in four probands within the four chromosomal loci 4q34-qter, 8p23.1, 10p14 and 22q11.2 implicated in almost all cases of DGS syndrome.</p> <p>Conclusion</p> <p>Uterovaginal aplasia appears to be an additional feature of the broad spectrum of the DGS phenotype. The DiGeorge critical chromosomal regions may be candidate loci for a subset of MRKH syndrome (MURCS association) individuals. However, the genes mapping at the sites of these deletions involved in uterovaginal anomalies remain to be determined. These findings have consequences for clinical investigations, the care of patients and their relatives, and genetic counseling.</p

Clinical and molecular characterization of 17q21.31 microdeletion syndrome in 14 French patients with mental retardation.

International audienceChromosome 17q21.31 microdeletion was one of the first genomic disorders identified by chromosome microarrays. We report here the clinical and molecular characterization of a new series of 14 French patients with this microdeletion syndrome. The most frequent clinical features were hypotonia, developmental delay and facial dysmorphism, but scaphocephaly, prenatal ischemic infarction and perception deafness were also described. Genotyping of the parents showed that the parent from which the abnormality was inherited carried the H2 inversion polymorphism, confirming that the H2 allele is necessary, but not sufficient to generate the 17q21.31 microdeletion. Previously reported molecular analyses of patients with 17q21.31 microdeletion syndrome defined a 493 kb genomic fragment that was deleted in most patients after taking into account frequent copy number variations in normal controls, but the deleted interval was significantly smaller (205 kb) in one of our patients, encompassing only the MAPT, STH and KIAA1267 genes. As this patient presents the classical phenotype of 17q21.31 syndrome, these data make it possible to define a new minimal critical region of 160.8 kb, strengthening the evidence for involvement of the MAPT gene in this syndrome

Expanding the clinical spectrum of hereditary fibrosing poikiloderma with tendon contractures, myopathy and pulmonary fibrosis due to <i>FAM111B </i>mutations

BACKGROUND: Hereditary Fibrosing Poikiloderma (HFP) with tendon contractures, myopathy and pulmonary fibrosis (POIKTMP [MIM 615704]) is a very recently described entity of syndromic inherited poikiloderma. Previously by using whole exome sequencing in five families, we identified the causative gene, FAM111B (NM_198947.3), the function of which is still unknown. Our objective in this study was to better define the specific features of POIKTMP through a larger series of patients. METHODS: Clinical and molecular data of two families and eight independent sporadic cases, including six new cases, were collected. RESULTS: Key features consist of: (i) early-onset poikiloderma, hypotrichosis and hypohidrosis; (ii) multiple contractures, in particular triceps surae muscle contractures; (iii) diffuse progressive muscular weakness; (iv) pulmonary fibrosis in adulthood and (v) other features including exocrine pancreatic insufficiency, liver impairment and growth retardation. Muscle magnetic resonance imaging was informative and showed muscle atrophy and fatty infiltration. Histological examination of skeletal muscle revealed extensive fibroadipose tissue infiltration. Microscopy of the skin showed a scleroderma-like aspect with fibrosis and alterations of the elastic network. FAM111B gene analysis identified five different missense variants (two recurrent mutations were found respectively in three and four independent families). All the mutations were predicted to localize in the trypsin-like cysteine/serine peptidase domain of the protein. We suggest gain-of-function or dominant-negative mutations resulting in FAM111B enzymatic activity changes. CONCLUSIONS: HFP with tendon contractures, myopathy and pulmonary fibrosis, is a multisystemic disorder due to autosomal dominant FAM111B mutations. Future functional studies will help in understanding the specific pathological process of this fibrosing disorder

Effects of eight neuropsychiatric copy number variants on human brain structure

Many copy number variants (CNVs) confer risk for the same range of neurodevelopmental symptoms and psychiatric conditions including autism and schizophrenia. Yet, to date neuroimaging studies have typically been carried out one mutation at a time, showing that CNVs have large effects on brain anatomy. Here, we aimed to characterize and quantify the distinct brain morphometry effects and latent dimensions across 8 neuropsychiatric CNVs. We analyzed T1-weighted MRI data from clinically and non-clinically ascertained CNV carriers (deletion/duplication) at the 1q21.1 (n = 39/28), 16p11.2 (n = 87/78), 22q11.2 (n = 75/30), and 15q11.2 (n = 72/76) loci as well as 1296 non-carriers (controls). Case-control contrasts of all examined genomic loci demonstrated effects on brain anatomy, with deletions and duplications showing mirror effects at the global and regional levels. Although CNVs mainly showed distinct brain patterns, principal component analysis (PCA) loaded subsets of CNVs on two latent brain dimensions, which explained 32 and 29% of the variance of the 8 Cohen’s d maps. The cingulate gyrus, insula, supplementary motor cortex, and cerebellum were identified by PCA and multi-view pattern learning as top regions contributing to latent dimension shared across subsets of CNVs. The large proportion of distinct CNV effects on brain morphology may explain the small neuroimaging effect sizes reported in polygenic psychiatric conditions. Nevertheless, latent gene brain morphology dimensions will help subgroup the rapidly expanding landscape of neuropsychiatric variants and dissect the heterogeneity of idiopathic conditions

Copy number variation goes clinical

A report of the First Golden Helix Symposium 'Copy Number Variation (CNV) and Genomic Alterations in Health and Disease', Athens, Greece, 28-29 November 2008

Prédispositions héréditaires aux cancers du sein et/ou de l'ovaire (expérience Lorraine : de la caractérisation de mutations délétères au sein du gène BRCA1)

NANCY1-SCD Medecine (545472101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Les insertions chromosomiques en pathologie constitutionnelle

Les insertions sont des réarrangements chromosomiques rares résultant d'erreurs de réparation d'au moins trois points de cassures double-brin. Elles sont définies par la délocalisation d'un fragment intercalaire d'un chromosome ailleurs dans le génome. On les qualifie d'inter- ou intrachromosomiques, équilibrées ou déséquilibrées, directes ou inversées. Les porteurs d'une insertion chromosomique équilibrée peuvent être asymptomatiques mais risquent de transmettre des déséquilibres chromosomiques pouvant être responsables de retard mental et/ou de malformations, ou de fausses-couches spontanées. Les trois familles décrites dans ce manuscrit illustrent plusieurs types d'insertions et survenant dans des contextes cliniques très différents. Il n'existe pas de phénotype typique d'une insertion chromosomique. Leur découverte dans une famille implique un risque de récidive d'un déséquilibre chromosomique à chaque grossesse. Il est donc indispensable de pouvoir les identifier pour délivrer un conseil génétique adapté à la famille. L'analyse, à la fois qualitative et quantitative d'une région chromosomique d'intérêt permise par l'hybridation in situ, en fait une technique de choix pour la détection des insertions chromosomiques.NANTES-BU Médecine pharmacie (441092101) / SudocSudocFranceF