Neurofibromatosis 2 and neurilemmomatosis gene are identical

Neurofibromatosis 2 (NF2) is an autosomal dominant disorder characterized by the occurrence of bilateral acoustic neuromas, as well as meningiomas and schwannomas. The gene locus for NF2 resides on chromosome 22q12 and has been cloned recently. Neurilemmomatosis is characterized by multiple cutaneous and spinal neurilemmomas without other signs of NF1 or NF2. Many cases with this disorder include the diagnosis of neurofibromatosis or other rare diseases unexplained by current nosology. In this study, we analyzed the peripheral leukocytes and tissue from cutaneous neurilemmomas of seven patients with neurilemmomatosis using DNA markers for different regions of chromosome 22. We detected allelic losses in three of seven tumors from seven patients with a probe for the NF2 region of the long arm of chromosome 22 and the germ-line mutations in two of three tumors from the same three patients. Mutations in the NF2 gene were a deletion from at least codon 334 to 579 and G insertion at codon 42. We conclude that the neurilemmomatosis locus lies within the NF2 region and that these diseases might be identical.