Mutations in a number of different genes encoding SWI/SNF chromatin remodelling complex proteins have been described but the underlying molecular cause remains unknown in approximately 40% of patients with CSS.
Heterozygous mutations in genes encoding subunits of the SWI/SNF complex have been reported in individuals with Coffin-Siris syndrome (CSS), with the majority of the mutations in ARID1B.
Beyond neoplasms, several congenital developmental functional disorders such as Coffin-Siris syndrome and intellectual disability are now known to be SWI/SNF-related.
Mutations in the BAF complex (mammalian SWI/SNF complex) are responsible for Coffin-Siris syndrome, which is characterized by developmental delay, distinctive facial features, hirsutism, and hypoplasia/aplasia of the fifth finger/fingernails.
As SMARCB1 encodes a subunit of the SWItch/Sucrose NonFermenting (SWI/SNF) complex, we screened 15 other genes encoding subunits of this complex in 23 individuals with CSS.