When including CNV losses and sequence variants from DECIPHER, the top mSWI/SNF genes implicated were SMARCB1 and SMARCA2, mutations in which cause the most severe phenotypes of mSWI/SNF-related NDDs, CSS and Nicolaides-Baraitser syndrome (NCBRS), respectively85 (Fig. 1c). Here, SMARCB1 is linked to Coffin-Siris syndrome.