NF2 and schwannoma: Moreover, schwannomas of patients with germline SMARCB1 mutations may follow the 5-hit/3-step model if the chromosomal region on chromosome 22 exhibiting LOH also includes LZTR1. Since LZTR1 is located proximal to SMARCB1 and NF2, the loss of one LZTR1 allele is dependent upon the extent of the region showing LOH.