Neurofibromatosis type 2 is a genetic disease caused by a mutation, i.e. a change in the genetic material. The affected gene encodes a protein called merlin, or sometimes schwannomin as well. Merlin is mainly present in nerve tissues and functions as a tumor suppressor; in other words, it counteracts the development of tumors by inhibiting growth.
NF2 occurs in around 1:25.000-33.000 people. Somewhat more than one third of the cases are passed down by parents to their children; heredity is therefore autosomal dominant. This means that the probability of passing on the disease (heredity) is 50%. Somewhat fewer than 2/3 of the cases are due to a spontaneous or new mutation, called a de novo mutation. This means that the gene change has newly occurred in the patient himself or herself.
Genetic testing is possible and recommended for everyone with the clinical diagnosis and for all patients with tumors typical of NF2 (meningiomas, schwannomas) to verify the diagnosis. Genetic testing of people who are potentially affected but do not have symptoms is advised from the age of 10-12.