Altogether, these results indicated that the presence of schwannomas confined to one limb were caused by a first hit, the loss of one copy of 22q12.1q13.33, involving the NF2 gene and affecting at least the schwannoma-initiating cells present in this limb segment, followed by second hits inactivating the remaining functional copy of NF2 as an independent event in each schwannoma developed. This evidence concerns the gene NF2 and schwannoma.