Neurofibromatosis 2: clinical and DNA linkage studies of a large kindred.

At least eight provisional categories of neurofibromatosis have been proposed. Among these, neurofibromatosis 1 (von Recklinghausen's disease or peripheral neurofibromatosis) and neurofibromatosis 2 (central or bilateral acoustic neurofibromatosis) have been established as distinct disorders. We studied 15 affected male and 8 affected female members of one large kindred with neurofibromatosis 2. None of the patients met the diagnostic criteria for neurofibromatosis 1. Between the ages of 15 and 53 years, the patients had multiple central nervous system tumors of various types--mainly, bilateral acoustic neuromas. Two or more tumors eventually developed in 20 of the patients; 9 had evidence of only bilateral acoustic neuromas. Meningiomas and ependymomas were more common among the young patients; those who initially presented with acoustic neuromas were nearly a decade older. Intracranial nontumoral calcifications were present in most patients and were also found in symptom-free children. The presence of such lesions is probably a prodromic feature of neurofibromatosis 2. Simultaneous analysis of D22S1 and IGLV DNA markers for coinheritance with neurofibromatosis 2 indicates that the locus for the disease is near the center of the long arm of chromosome 22 (22q11.1----22q13.1). The eventual isolation of this disease gene may reveal a cause of the most common intracranial tumors in humans.