Neurofibromatosis Type 2 Diagnosis
The diagnosis of Neurofibromatosis Type 2 (NF2) is best made by an NF expert, and is based on a physical examination, MRI imaging, family history, and personal history of hearing loss. Genetic testing for NF2 is often but not always helpful, since the blood cells that are sent for genetic testing do not always carry the NF2 mutation. People who are diagnosed with NF2 often complain of ringing in their ears (tinnitus), hearing loss, balance difficulties, facial droop or weakness on one side, and vision loss as a child or teenager due to cataracts. The NF2 mutation causes the overgrowth of cells that wrap around and insulate nerves. The result is the growth of tumors known as schwannomas. NF2 patients are also at risk of other conditions, as mentioned below.
Vestibular schwannomas are tumors that grow inside the skull within the nerve that carries hearing and balance information from the ears to the brain (vestibular nerve). If these tumors are present on both sides -- in both vestibular nerves-- this can qualify someone for a diagnosis of NF2. NF2 patients are also predisposed to develop meningiomas, tumors that grow in the lining around the brain, and ependymomas, tumors that grow along the fluid-filled spaces in the brain. These tumors are usually benign (meaning they are not cancers and will not move to other places in the body), but they can cause symptoms including but not limited to pain, hearing loss, dizziness, or weakness, depending on where in the nervous system they are located.
NF2 is a heritable condition, and each child of a parent with NF2 has a 50 percent risk of also being affected. In other words, there is a 50 percent risk of passing along the condition to each child. Although genetic analysis is not recommended in every case, it can be helpful in some situations when the diagnosis is unclear.
The diagnostic criteria for NF2 include any one of the following major bullets:
- A Vestibular Schwannoma (pronounced shwah-NO-ma) in both vestibular nerves
- A parent or sibling diagnosed with NF2, and:
- One vestibular schwannoma, OR
- At least two added features*
- One vestibular schwannoma and two added features*
- At least two meningiomas and:
- One vestibular schwannoma, OR
- Two added features*
* Added features contributing to a diagnosis of NF2
- A meningioma
- A brain or spinal cord tumor known as a glioma (including a subtype called ependymoma)
- A schwannoma growing along another nerve (not the vestibular nerve)
- Cataracts as a child or teenager
- A neurofibroma (this is unlikely to be found in NF2 and is far more likely to be associated with NF1)
Neurofibromatosis Type 2 Treatment
There is no genetic cure for Neurofibromatosis Type 2. Treatment involves regular imaging and appointments with an NF expert to monitor the growth of associated tumors, and regular hearing tests. Tumors may need to be surgically removed, and radiation may be recommended. Hearing loss is treated with hearing aids, cochlear implantation, and in some cases with a medication known as Avastin (bevacizumab) which can reduce tumor size and improve hearing in some people with symptomatic vestibular schwannomas. The Neurofibromatosis Clinic at Mount Sinai includes surgeons, radiologists, ENT doctors, neuro-otologists (hearing specialized neurologists), and oncologists, and is dedicated to clinical trials research in NF2 to improve the physical and mental health of our patients.