[1] It is characterized by impaired intellectual development, macrocephaly, dysarthria and apraxia of speech, and certain distinctive facial features.

[2] Snijders Blok–Campeau syndrome is typically a de novo mutation[3][4] which generally occurs during the early embryonic stages of development or during the formation of the parent's reproductive cells.

Around one half typically have some form of macrocephaly, while around one third show signs of autism or similar conditions.

[7] By allowing for the creation of chromatin, the CHD3 gene affects how tightly DNA is packed into chromosomes.

[7][8] Due to the rarity of the condition, with only approximately 60 cases documented in scientific literature,[7] Snijders Blok–Campeau syndrome was only discovered in 2018 by clinical geneticist Lot Snijders Blok and clinician-scientist Philippe M Campeau.