Delineation of the 3p14.1p13 microdeletion associated with syndromic distal limb contractures
International audience; Distal limb contractures (DLC) represent a heterogeneous clinical and genetic condition. Overall, 20–25% of the DLC are caused by mutations in genes encoding the muscle contractile apparatus. Large interstitial deletions of the 3p have already been diagnosed by standard chromosomal analysis, but not associated with a specific phenotype. We report on four patients with syndromic DLC presenting with a de novo 3p14.1p13 micro-deletion. The clinical features associated multiple contractures, feeding problems, developmental delay, and intellectual disability. Facial dysmorphism was constant with low-set posteriorly rotated ears and blepharophimosis. Review of previously r…
Phenotypic spectrum and genomics of undiagnosed arthrogryposis multiplex congenital
BackgroundArthrogryposis multiplex congenita (AMC) is characterised by congenital joint contractures in two or more body areas. AMC exhibits wide phenotypic and genetic heterogeneity. Our goals were to improve the genetic diagnosis rates of AMC, to evaluate the added value of whole exome sequencing (WES) compared with targeted exome sequencing (TES) and to identify new genes in 315 unrelated undiagnosed AMC families.MethodsSeveral genomic approaches were used including genetic mapping of disease loci in multiplex or consanguineous families, TES then WES. Sanger sequencing was performed to identify or validate variants.ResultsWe achieved disease gene identification in 52.7% of AMC index pati…
Xq28 duplication includingMECP2in six unreported affected females: what can we learn for diagnosis and genetic counselling?
Duplication of the Xq28 region, involving MECP2 (dupMECP2), has been primarily described in males with severe developmental delay, spasticity, epilepsy, stereotyped movements and recurrent infections. Carrier mothers are usually asymptomatic with an extremely skewed X chromosome inactivation (XCI) pattern. We report a series of six novel symptomatic females carrying a de novo interstitial dupMECP2, and review the 14 symptomatic females reported to date, with the aim to further delineate their phenotype and give clues for genetic counselling. One patient was adopted and among the other 19 patients, seven (37%) had inherited their duplication from their mother, including three mildly (XCI: 70…
Clinical Utility of a Unique Genome-Wide DNA Methylation Signature for KMT2A-Related Syndrome
Wiedemann–Steiner syndrome (WDSTS) is a Mendelian syndromic intellectual disability (ID) condition associated with hypertrichosis cubiti, short stature, and characteristic facies caused by pathogenic variants in the KMT2A gene. Clinical features can be inconclusive in mild and unusual WDSTS presentations with variable ID (mild to severe), facies (typical or not) and other associated malformations (bone, cerebral, renal, cardiac and ophthalmological anomalies). Interpretation and classification of rare KMT2A variants can be challenging. A genome-wide DNA methylation episignature for KMT2A-related syndrome could allow functional classification of variants and provide insights into the pathoph…