NF2 is much rarer than NF1, occurring in 1 in 25,000 births. Tumors affecting both of the auditory nerves (nerves that carry signals from the ear to the brain) are the hallmark of NF2, so the first symptom is often hearing loss beginning in the teens or early 20s. NF2 is characterized by multiple tumors on the cranial and spinal nerves, and by other lesions of the brain and spinal cord. NF2 is also known as Bilateral Acoustic NF (BAN).
Because NF2 is so rare, few studies have been done about the natural progression of the disorder. The course of NF2 varies greatly among individuals, although inherited NF2 appears to run a similar course among affected family members.
Signs of NF2 may be present in childhood, but are so subtle that they can be overlooked, especially in children who do not have a family history of the disorder. Typically, symptoms of NF2 are noticed between 18 and 22 years of age.
The most frequent first symptom is hearing loss or ringing in the ears (tinnitus). Less often, the first visit to a doctor will be because of disturbances in balance, vision impairment (such as vision loss from cataracts), weakness in an arm or leg, seizures or skin tumors.
There is no medical cure for NF2 and the treatment is mainly focused on diagnosing and treating the acoustic neuromas early and preventing hearing loss or facial paralysis. Improved diagnostic technologies, such as MRI (magnetic resonance imaging), can reveal tumors as small as a few millimeters in diameter, which allows for early treatment.
Some families and doctors may choose to use a genetic test to confirm an uncertain diagnosis of NF2. However, new (spontaneous) mutations cannot be confirmed genetically. Genetic testing for the NF2 mutation is available but is accurate in only 65% of those tested. Genetic counselors can provide information about these procedures and help families cope with the results.
Genetic counseling can help couples affected by NF to work through the decision-making processes as they plan to have a baby.