[Nonsense mutation 193C>T of neurofibromatosis type 2--a neurosurgical challenge].

A 15 years old male was operated because of incidentally found intercostal schwannoma. Two years later severe cerebellar ataxia and left sided anacusis developed. MRI revealed bilateral vestibularis tumors and multiple cervical intradural extramedullary myelin compressing lesions. After partial resection of the huge left sided cerebello-pontine tumor, histologically schwannoma, and the extirpation of the multiple cervical meningiomas the patient died three months later due to septic complications. The 24 years old mother had been operated on similar lesions 12 years earlier, after two weeks postoperative period she died. Her 14 years old twins are living, a boy also with bilateral acoustic tumours and a girl who is intact. Genetic investigation revealed C>T nonsense mutation at position 193 in the exon 2 of the NF2 gene. This mutation cause premature truncation of the gene protein and is probably in connection with the clinically severe phenotype. Early diagnosis of this type of neurofibromatosis is mandatory concerning the therapy.