Pathogenic variants (PVs) in LZTR1 or SMARCB1 are detected in approximately 86% of familial and ∼40% of sporadic schwannomatosis cases utilizing standard clinical mutation analysis including exons and intronic segments at exon boundaries (typically ± 20 nucleotides) [33–36, 38, 40, 42, 65, 67, 68, 362, 363]. Here, SMARCB1 is linked to schwannomatosis.