GERMLINE SCREENING OF THE NF-2 GENE IN FAMILIES WITH UNILATERAL VESTIBULAR SCHWANNOMA

Vestibular schwannoma may present clinically in two forms: sporadic un ilateral or hereditary bilateral. Familial transmission of vestibular schwannoma is known to occur only in neurofibromatosis type II (NF-2). We have previously described the clinical characteristics of unilater al vestibular schwannoma presenting in families, in the absence of the r criteria necessary for the diagnosis of NF-2. Polymerase chain react ion-single strand chain polymorphism was used to screen for germline N F-2 gene mutations in six families with unilateral vestibular schwanno ma. Direct sequencing of DNA from blood was done in affected subjects from three families. Na germline mutations were identified. Because NF -2 gene mutations are detected in only 33% of patients with NF-2, here ditary transmission of mutations cannot be entirely excluded. However, in the absence of germline mutations in the NF-2 gene, familiar occur rence of unilateral vestibular schwannoma more likely represents eithe r a chance somatic NF-2 gene mutation or originates from a separate ge netic loci.