In addition, molecular tumorigenesis mechanisms in both SMARCB1‐ and LZTR1‐associated schwannomatosis do not conform to the classic Knudson two‐hit model hypothesis, but instead follow a four‐hit/three‐step model that includes loss of heterozygosity (LOH) of the wild‐type allele and somatic biallelic inactivation of the NF2 (MIM# 607379) gene (Kehrer‐Sawatzki et al., 2017; Sestini et al., 2008). This evidence concerns the gene SMARCB1 and schwannomatosis.