Sensorineural hearing loss (SNHL) is a hallmark symptom in patients with neurofibromatosis type 2-associated schwannomatosis (NF2-SWN), a genetic condition caused by mutations in the Neurofibromin II gene that encodes the tumor suppressor protein Moesin-Ezrin-Radixin-Like Protein (Merlin; also known as schwannomin). The gene discussed is TCHP; the disease is NF2-related schwannomatosis.