Snijders Blok-Campeau syndrome (SNIBCPS) is an autosomal dominant genetic disorder caused by usually de novo heterozygous variants (i.e. only one of the two copies has a variant, and that variant is usually absent from the parents if unaffected) that affect CHD3 function. Variants in CHD3 generally lead to a speech and language delay/disorder (100%, 35/35 individuals in an initial cohort). All individuals are diagnosed with intellectual disability. However, the severity varied from borderline in the normal range (9%), to severe (20%). In addition, the majority (85%) of individuals have a broad, high or prominent forehead.