What is neurofibromatosis?
Neurofibromatosis is a rare genetic disorder of the nervous system. The nervous system mainly affects how nerve cells form and grow, but neurofibromatosis causes tumors to form on this healthy nerve tissue. Usually these tumors are benign, but sometimes they can become cancerous.
There are three types of neurofibromatosis, which are distinguished based on some characteristic symptoms and sometimes genetic testing:
- Type 1 (NF1): causes skin changes and deformed bones; usually starts in childhood with the symptoms present at birth
- Type 2 (NF2): causes hearing loss, ringing in the ears, and poor balance; symptoms often start in the teen years
- Schwannomatosis: causes intense pain; the rarest type
What causes neurofibromatosis?
Neurofibromatosis is caused by genetic defects (mutations) that either are inherited or spontaneously occur. The specific genes that are involved depend on the type of neurofibromatosis.
- Type 1: The NF1 gene is mutated, causing a loss of the protein neurofibromin, which normally helps regulate cell growth
- Type 2: The NF2 gene is mutated, causing a loss of the protein merlin, which leads to uncontrolled cell growth
- Schwannomatosis: There are mutations in either the SMARCB1 gene or NF2 gene
The inheritance pattern for NF1 and NF2 is autosomal dominant, but the inheritance pattern for schwannomatosis is less clear.
What are the symptoms of neurofibromatosis?
Additional signs and symptoms of neurofibromatosis (by type) are the following:
- Type 1
- Flat, light brown spots on the skin and freckling in the armpits or groin area
- Tiny bumps on the iris of the eyes
- Soft bumps on or under the skin (neurofibromas)
- Bone deformities
- Larger than average head size and short stature
- Learning disabilities
- Type 2
- Gradual hearing loss, ringing in ears
- Poor balance or headaches
- Tumors on the skull, spinal and peripheral nerves
- Numbness or weakness in various parts of the body
- Loss of muscle
How is neurofibromatosis diagnosed?
A health care provider will begin with a review of family and personal medical history, a clinical evaluation can usually make a diagnosis of neurofibromatosis. In addition, an eye exam, ear exam, genetic tests, and various imaging tests may also be used to confirm a diagnosis.
If there is no family history of the disease, there must be at least two signs of the condition for a diagnosis to be made.
What are the available treatments for neurofibromatosis?
Although there is no cure for any type of neurofibromatosis, treatment and monitoring can help control the symptoms of the disease, maximize healthy growth and development, and manage complications as soon as they arise.
The following procedures can help to treat severe symptoms or complications of neurofibromatosis:
- Surgery to remove tumors
- Stereotactic radiosurgery
- Auditory brainstem implants and cochlear implants