A Korean boy with a CHD8 mutation who presented with overgrowth, intellectual disability, and autism.

Abstract

The CHD8 mutation was initially identified as the cause of autism spectrum disorder (ASD) and was previously marked as Autism, susceptibility to, 18 [MIM 615032] on Online Mendelian Inheritance in Man (OMIM). As many patients with CHD8 mutation showed other characteristics along with autism, the phenotype was relabeled as intellectual developmental disorder with autism and macrocephaly (IDDAM) in May 2022. We report a 3-year 10-month-old boy who presented with overgrowth, intellectual disability, dysmorphic facial features, and ASD. Targeted exome sequencing identified a heterozygous nonsense mutation c.2854C>T (p.Arg952Ter) in CHD8, and he was diagnosed with IDDAM. Overgrowth patients with dysmorphic face and/or developmental delay should be investigated for genetic causes. Such causes have been reported in about 50% of patients diagnosed with overgrowth with intellectual disability. Our case suggests that CHD8 genetic testing should be included if overgrowth, intellectual disability, and ASD coexist.