BAF47, also known as INI1 and SNF5, is a known tumor suppressor whose biallelic inactivation is responsible for ~100% of the cases of malignant rhabdoid tumor (MRT), an aggressive childhood tumor in soft tissues (Biegel et al., 2002). While the cancer mutations in BAF47 are inactivating and lead to loss of heterozygosity, de novo BAF47 mutations found in CSS patients are not truncating and act in a genetically dominant manner. The CSS mutations are exclusively located in the positively charged lysine or arginine residues in the hydrophilic C-terminus of BAF47 (Figure 2) (Tsurusaki et al., 2013, 2012; Santen et al., 2013). One recurrent in-frame deletion (p.Lys364del) is found in 9 unrelated patients, suggesting a critical role for this residue in the function of BAF47 within the CNS.
