The Genetics of Vestibular Schwannoma

Abstract

Vestibular Schwannoma (VS) results from mutations/deletions of both copies of the NF2 gene on chromosome of 22q12, with lifetime risk estimated at one in 1,000. Bilateral VS is the hallmark of the autosomal dominant inherited tumour predisposition syndrome Neurofibromatosis type 2 (NF2), but the majority of VS are due to sporadic mutations. Estimations indicate that 33 % of de novo patients with bilateral VS and up to 60 % with unilateral VS have mosaicism for an NF2 mutation. Hundreds of mutations of the NF2 gene have been described, with truncating mutations (nonsense and frameshifts) leading to a severe phenotype. Despite advances in understanding, the relation between the genotype and phenotype in VS is not fully understood and the mechanisms leading to inactivation of the NF2 gene have not been fully characterised. As the genetics underlying VS is increasingly demystified targeted therapies offer hope in cases of progressive VS where existing treatment fails.