These include approximately 900 different somatic cancer mutations (Tate et al. 2019; COSMIC Cancer database, https://cancer.sanger.ac.uk/cosmic), including whole gene deletions and point mutations such as SMARCB1 c.1148del/p.P383RfsX100 (COSM1057), as well as neurodevelopmental disorders such as intellectual disability with plexus hyperplasia and the Coffin–Siris syndrome. The gene discussed is SMARCB1; the disease is neurodevelopmental disorder.