NEUROFIBROMATOSIS TYPE 2 (CENTRAL NEUROFIBROMATOSIS OR BILATERAL ACOUSTIC NEUROMAS, VESTIBULAR SCHWANNOMAS): FROM PHENOTYPE TO GENE
Summary. Neurofibromatosis type 2 (NF2) is an autosomal dominant disease that predisposes to bilateral vestibular schwannomas (neurinomas), other central and peripheral nervous system tumours (multiple meningeomas and neuro- fibromas) and ocular abnormalities (cataract). The NF2 tumour suppresor gene is localised on chromosome 22q12 and encodes protein called schwannomin or merlin which is related to a family of cytoskeleton-to-membrane proteins linkers ERM (ezrin-radixin-moesin proteins). About 50% of all cases are new germline mutations, although about 20% of appar- ently sporadic cases represent somatic mosaicism. The majority of observed germline NF2 mutations are point mutations which result in schwannomin with an altered or absent C-terminal domain. NF2 has a variable clinical presentation, with two basic types: severe type having early onset and progressive growth of tumors and the milder type having later onset and less aggressive course. The genotype-phenotype correlations indicate a greater variability of clinical disease expression. In this paper we discuss the epidemiology, genetic and clinical characteristics, diagnostic criteria, investigations, screening for risk persons and recommendations for care and therapy of patients with NF2.