Neurobehavioral profile of individuals with pathogenic variants in CHD3

Snijders Blok-Campeau syndrome (SNIBCPS), a neurodevelopmental disorder first described in 2018, is caused by heterozygous pathogenic variants in CHD3. Its encoded protein plays a crucial role in the development of the nervous system of embryos. While phenotypic traits have been broadly defined (i.e. global neurodevelopmental delays such as intellectual disabilities and delayed speech acquisition, and physical features such as characteristic facial features and macrocephaly), the phenotypic spectrum has not been further assessed. We present the neurobehavioral profile of 38 individuals with variants in CHD3 and compare it to the ones of autism spectrum disorder (ASD) and Fragile X syndrome (FXS) cohorts. Profound clinical deficits were found in adaptive functioning, communication skills and sensorimotor functioning in most SNIBCPS participants. Similarities between FXS and SNIBCPS cohorts were unveiled, characterized by diminished levels of global adaptive behaviour and adaptive functioning in the social and communication domains. Nevertheless, despite profound challenges in global adaptive behavior in SNIBCPS, we reveal the social domain as showing the highest adaptive levels alongside minimal emotional/behavioural issues within the sample, suggesting relative strengths inherent to SNIBCPS. This study enriches the scarce SNIBCPS literature by delineating the neurobehavioral phenotypic spectrum of SNIBCPS and by innovating comparisons with clinically akin neurodevelopmental disorders.