Analysis of Genetic Mutations and the Clinical Manifestations of Neurofibromatosis Type 2 in Korea: A Single Institutional Experience

Abstract

Background and Objectives Neurofibromatosis type 2 (NF2) is a rare autosomal dominant disorder characterized as bilateral vestibular schwannoma (VS), various brain and spinal tumors. This study is aimed to investigate the relationship between the genotypes and phenotypes of NF2 found in the Korean population.Subjects and Method We retrospectively reviewed 11 patients who were diagnosed with NF2 and observed them for more than a year. NF2 gene mutations were detected using Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA). The mutations were classified into tissue mosaicism, classic, and severe genotypes according to the UK NF2 genetic severity score. Tumor load was assessed by reviewing MR images and audiological findings were analyzed.Results We identified 7 cases (63.6%) of mutations from 11 patients who were diagnosed with NF2. While three patients showed classic and four showed severe genotypes, four patients were presumed as tissue mosaicism. The patients with severe genotypes didn’t show more severe clinical manifestations in terms of tumor load and hearing. Four patients with tissue mosaicism were detected in the older age group than those with mutation. Of the five patients who had serviceable bilateral hearing at the initial diagnosis, all maintained their serviceable hearing during the follow-up.Conclusion Our results, which showed that the clinical manifestations of NF2 found in the Korean population have no correlation with the genotype findings, are not in agreement with previous studies. However, further studies with larger sample sizes are needed to give more appropriate counsel.