SMARCB1 and schwannomatosis: Whole-gene deletion and other copy-number variants in SMARCB1 are typically linked to rhabdoid tumor predisposition syndrome (RTPS) and have not been reported to cause schwannomas.6 Typically, schwannomatosis-associated SMARCB1 variants that cause around 40% of hereditary and 10% of sporadic schwannomatosis are “hypomorphic” with some presumed preserved function of the affected allele.6 This preserved function appears to be sufficient to prevent development of rhabdoid tumors in the critical first few years of life.