What is neurofibromatosis type 2 (NF2)?
Neurofibromatosis type 2 (NF2) is a genetic disorder that involves changes in the NF2 gene. This particular gene helps in the production of merlin (also called schwannomin), a protein that stops tumors from forming. The gene is located on chromosome 22.
The main trait of NF2 is that noncancerous (benign) tumors grow on the nerves of the brain and the spine. In NF2, the auditory nerves, the ones that involve hearing, are commonly affected. Therefore, hearing is affected. These types of tumors grow along the auditory nerve that connects the brain and inner ear. The tumors are called vestibular schwannomas or acoustic neuromas.
Schwannomas are tumors that are made up of Schwann cells. Very often, the tumors grow on the auditory nerves on both the left and right side of the brain and are called bilateral vestibular schwannomas. These types of tumors are the main feature of NF2. These tumors often appear before the person reaches age of 30.
Tumors can appear on the skin and on other parts of the nervous system as well, such as the brain and spinal cord.
Who gets neurofibromatosis type 2 (NF2)?
Various estimates put the number of people worldwide born with NF2 at 1 in 25,000 to 1 in 40,000. Both males and females are affected in equal numbers. All ethnic groups are affected. It can be inherited, but about half the people with NF2 have no family history. Because it can be inherited, the main risk factor is family history.
Children with NF2 tend to have symptoms related to tumors in the brain and spinal cord. Adults diagnosed with NF2 are usually in the age range of 18 to 24 years old. They tend to have problems due to tumors on the auditory nerves.
What are the symptoms of neurofibromatosis type 2 (NF2)?
Early symptoms of NF2 include:
- Problems with balance (such as dizziness).
- Problems with hearing.
- Ringing in the ears, also called tinnitus.
For tumors that occur outside of the auditory nerves, symptoms might include:
- Weakness in the face, arms or legs.
- Clouded lenses in one or both eyes (cataracts), often at a young age.
- Increase in fluid on the brain.