(von Recklinghausen's diseaase)
Neurofibromatosis (NF) is a genetic disorder of the nervous system. It causes tumors to grow on the nerves in any part of the body. Neurofibromatosis can also produce other abnormalities, such as changes in skin color and deformity of bones.
There are two types of neurofibromatosis, NF1 and NF2. They are caused by mutations (changes) of different genes. NF1 is more common and occurs with a frequency of 1 in 2,500 to 3,300 live births worldwide and NF-2 in 1 per 50,000 to 120,000.
Neurofibromatosis is caused by a change in a gene, called a mutation. In many cases the abnormal gene is inherited. However, frequently the gene changes occur by chance in a person with no family history of NF. A person with the inherited form of neurofibromatosis has a 50% chance of passing on the abnormal gene each time he or she has a child (Autosomal Dominant Trait). Also, all first-degree relatives (parents, children, and siblings) of an affected individual should be considered at risk and evaluated for signs of NF.
A risk factor is something that increases your chances of getting a disease or condition. The main risk factor for neurofibromatosis is having a family member with the disease.
NF1 and NF2 have different symptoms. With either type, the symptoms can range from mild to severe. In most cases the symptoms are mild and may be overlooked.Symptoms of NF1
- Light brown spots (called café-au-lait spots) on the skin
- Neurofibromas – tumors that grow on a nerve or nerve tissue
- Soft tumors which may have a darker color called plexiform neurofibromas
- Freckles in the armpits or groin
- Growths on the iris (colored part of the eye)
- Tumor on the optic nerve that may affect vision
- Severe scoliosis (curved spine)
- Deformed or enlarged bones other than the spine
- Mild impairment of intellectual function, attention deficit disorder
Most of these symptoms begin between birth and age 10. Neurofibromas rarely occur before puberty.
The diagnosis of neurofibromatosis is generally made based on physical findings. The cafe-au-lait spot (meaning literally the color of coffee with cream) is the hallmark of neurofibromatosis. Although many normal people have 1 or 2 small cafe-au-lait spots, adults with 6 or more spots greater than 1.5 cm in diameter are likely to have neurofibromatosis. Other signs include:
- Freckling in the armpits, groin, or underneath the breast in women
- Multiple soft tumors apparent on the skin or deeper in the body viewed by radiologic testing (scans)
- Soft nodules under the skin
- Large infiltrating tumors under the skin (plexiform neurofibromas) which can cause disfigurement
- Pigmented, raised spots on the colored part (iris) of the eye (Lisch nodules)
Tests may include:
Symptoms of NF2
- Examination by a doctor familiar with NF1, such as a neurologist, geneticist, or dermatologist
- Eye exam by an ophthalmologist familiar with NF1
- MRI of the affected site
- Removal of neurofibromas of skin lesions
- Other specific tests associated with complications
- Genetic testing that demonstrates a mutation in the neurofibromin gene
A person with NF2 has several tumors on the nerves of the brain and spine. Most common are tumors that affect the nerves to the ears. Hearing loss may begin as early as the teen years.
Other symptoms may include:
- Tinnitus (ringing in the ear)
- Poor balance
- Pain or numbness in the face
The doctor will ask about your symptoms and medical history, and perform a physical exam. Neurofibromatosis is diagnosed based on symptoms.
Genetic testing is available for families with documented cases of NF1 and NF2 based on clinical evaluations. New (spontaneous) mutations cannot be confirmed genetically. Prenatal diagnosis of familial NF1 or NF2 may be possible utilizing amniocentesis or chorionic villus sampling procedures if there is an identified change in the DNA from other affected family members that is the cause of NF.
Treatments for both types of neurofibromatosis are aimed at controlling symptoms that cause problems. Neurofibromatosis tumors are not always treated because they grow slowly, are rarely cancerous, and may not cause problems. People with neurofibromatosis need to have regular exams to check for changes in:
Treatment of NF1
- Brown spots on the skin
- Bones, including scoliosis
Surgery can help correct some bone abnormalities. Bone surgery may be combined with back braces to treat scoliosis. Surgery can also be used to remove painful or disfiguring tumors. However, tumors may grow back and in larger numbers. In rare cases when tumors become cancerous, treatment may include surgery, chemotherapy, or radiation.
Treatment of NF2
Surgery can remove tumors, but it may damage the nerves. If the nerves to the ears are damaged, hearing loss can occur. Other treatment options include partial removal of tumors and radiation. MRI scans of the brain can locate tumors when they are small so treatment can be started early.
There are no guidelines for preventing neurofibromatosis.