De novo variants in the Helicase-C domain of CHD8 are associated with severe phenotypes including autism, language disability and overgrowth

AbstractCHD8, which encodes Chromodomain helicase DNA-binding protein 8, is one of a few well-established Autism Spectrum Disorder (ASD) genes. Over 60 mutations have been reported in subjects with variable phenotypes, but little is known concerning genotype –phenotype correlations. We have identified four novel de novo mutations in Chinese subjects: two nonsense variants (c.3562C>T/p.Arg1188X, c.2065C>A/p.Glu689X), a splice site variant (c.4818-1G>A) and a missense variant (c.3502T>A/p.Tyr1168Asn). Three of these were identified from a 445-member ASD cohort by ASD gene panel sequencing of the 96 subjects who remained negative after molecular testing for copy number variation, Rett syndrome, FragileX and tuberous sclerosis complex (TSC). The fourth (p.Glu689X) was detected separately by diagnostic trio exome sequencing. We used diagnostic instruments and a comprehensive review of phenotypes, including prenatal and postnatal  growth parameters, developmental milestones, and dysmorphic features to compare these four subjects. In addition to autism, they also presented with prenatal onset macrocephaly, intellectual disability, overgrowth during puberty, sleep disorder, and dysmorphic features, including broad forehead wi th prominent supraorbital ridges, flat nasal bridge, telecanthus and large ears. For further comparison, we compiled a comprehensive list ofCHD8 variants from the literature and databases, which revealed constitutive and somatic truncating variant...
Source: Human Genetics - Category: Genetics & Stem Cells Source Type: research