The recognition that mutations in the SMARCB1 gene predispose to benign schwannoma, which usually become symptomatic during adulthood, came as something of a surprise, since this gene was originally discovered in the context of its involvement in the development of atypical teratoid/rhabdoid tumours (Versteege et al. 1998; Sévenet et al. 1999a). The gene discussed is SMARCB1; the disease is schwannoma.