Neurofibromatosis

Neurofibromatosis (NF) is a condition that causes tumors to grow on nerve tissue, producing skin and bone abnormalities. NF is often diagnosed in childhood, occasionally in infancy but usually around 3-16 years of age. The effects of the disease vary widely. Some children might live almost unaffected by the condition. Although rare, others might be severely disabled.

Children with more severe forms of the disorder are usually diagnosed in infancy. Although there's no specific cure for NF, tumors can usually be removed and related complications can be treated. Children with NF may need some additional help in the classroom, because learning disabilities are seen in about half of children with the disease.

What Is Neurofibromatosis?

Neurofibromatosis is a neurocutaneous syndrome, it's passed down through the parents' genes, and it affects the brain, spinal cord, nerves, and skin.

Neurofibromatosis is defined by tumors, called neurofibromas, that grow along nerves in the body, or on or under the skin. As the tumors increase in size, they can press on vital areas of the body, causing problems in the way the body functions. It's not uncommon for neurofibromas to first appear during childhood, especially during puberty. One of the first noticeable signs of the disorder is almost always cosmetic disfigurement caused by these tumors (commonly called café-au-lait spots due to their distinctive light brown color). These distinctive spots can show up anywhere on the body.

Neurofibromas can often be removed. Although usually benign (noncancerous), they can sometimes become cancerous (in an estimated 5% of cases).

There are two types of neurofibromatosis, referred to as NF1 and NF2. NF1 is more common, occurring in one of every 4,000 births, and affecting an estimated 100,000 Americans. It is also known as von Recklinghausen disease.

The second type, NF2, is known as bilateral acoustic neurofibromatosis and is rarer, seen in one in 50,000 births. People with NF2 usually develop tumors on the nerves in their ears, causing hearing loss, eventual deafness, and problems with balance.

In both types of neurofibromatosis, the severity of the disorder varies greatly. In families where more than one person has NF, the disorder can progress with different physical signs and complications for each person. When NF is first diagnosed in a child, it isn't possible to know right away if the child will have a mild form of the disease or will develop severe complications.

What Causes Neurofibromatosis?

Both types of neurofibromatosis are autosomal dominant genetic disorders, which means a child has a 50% chance of inheriting the disease if either parent has NF. Neurofibromatosis can also be the result of a spontaneous change (mutation) in the genetic material of the sperm or egg at conception in families with no previous history of the disease. About half of cases of neurofibromatosis are inherited, and the other half result from genetic mutation.

There are two genes involved in causing neurofibromatosis. The NF1 gene is located on chromosome 17, and NF2 has been traced to chromosome 22. These findings are important because they may eventually lead to the development of a blood test or other genetic test to find out if a relative has NF.