Snijders Blok-Campeau syndrome is a rare genetic condition characterised by intellectual disability, speech problems, and distinctive facial features. The condition arises through mutations in the CHD3 gene, whose protein product regulates gene activity through chromatin remodelling and is involved in many developmental processes including cell growth and maturation of nerve cells.
Individuals with this syndrome experience intellectual disability ranging from mild to severe, often accompanied by low muscle tone, seizures, or autistic behaviours. Speech development is typically delayed, with some people developing limited language after age 2, whilst others may never speak or acquire only a few words. Despite communication challenges, affected individuals generally have very social personalities.
Distinctive facial features include widely spaced or deep-set eyes, sparse eyebrows, full cheeks, pointed chin, prominent forehead, and low-set ears. Most individuals have an abnormally large head, though some may have a small head, and about half have brain abnormalities such as enlarged fluid-filled spaces. Vision problems are common, and some may have heart defects.
The condition is inherited in an autosomal dominant pattern, though most cases result from new mutations occurring during reproductive cell formation or early development. The prevalence is unknown, but it is considered rare, with approximately 60 cases described in scientific literature.
Source:Medline Plus
