Background: Autism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental disorders. Genetically based subtype identification may prove more beneficial not only in illuminating the course and prognosis, but also for individualized treatment targets of an ASD sub-group. Increasing evidence has shown that de novo loss-of-function mutations in the chromodomain helicase DNA-binding protein 8 (CHD8) gene are associated with an ASD sub-group.
Case presentation: Here we describe two ASD cases in children with mild intellectual disability, early motor deficits, and speech delay, without distinct structural or EEG brain anomalies. Exome sequencing revealed a novel heterozygous nonsense/missense mutations(c.2647C > A/p.E883X and c.1677C > A/p.M559I respectively) in CHD8 gene.
Conclusions: There were few cases in the literature reporting de novo mutation of CHD8 in ASD. As demonstrated in our patients, along with other previously reported studies support that disruption of the CHD8 gene represents a specific genetic sub-type of ASD.
Keywords: Autism spectrum disorders; Chromodomain helicase DNA-binding protein 8; Next-generation sequencing.