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The University of Chicago Medicine - Comer Children's Hospital

Understanding Neurofibromatosis

What Is NF?

Neurofibromatosis is a genetic disorder that causes growths of tumors to form on nerves. These may occur anywhere in the body. NF is one of the most common genetic disorders. It occurs in every racial and ethnic group and affects both sexes equally. There are at least 100,000 people in the United States with NF. One in every 3,000 to 4,000 babies born has NF. In a city the size of Chicago, as many as 2,300 people have NF. But even though NF is relatively common, not many people have heard about it.

What Causes NF?

Neurofibromatosis is actually the name for a least two separate disorders, which can affect the nervous system as well as a number of other parts of the body. A genetic disorder is caused by an abnormal gene in your body. NF is not contagious. That means you can’t catch it from other people. However, parents may pass NF on to their children. It is important to understand the two ways children are born with NF:

  • You can inherit an abnormal gene that causes NF from one of your parents OR
  • Something can go wrong in one of your genes before birth. This second way of getting NF is called spontaneous gene mutation. If you have a spontaneous gene mutation, you did not inherit NF, but you can pass it on to your children.

We call NF two disorders because two different genes are affected. NF-1 is caused by a change in a gene on chromosome 17. NF-2 is caused by a change in a gene on chromosome 22. Because NF-1 and NF-2 are due to changes in different genes, NF-1 and NF-2 do not occur in the same family.

NF Can Be Caused by Spontaneous Gene Mutation
One member of this family--the baby--has NF. Since neither parent has the disease, the baby has NF due to spontaneous change in one of his or her genes. Because this is a spontaneous gene mutation, none of the baby's brothers or sisters is likely to have NF.

NF Is Dominantly Inherited
In this family, the mother has an abnormal gene that has caused NF, and two of her children have inherited this abnormal gene. Everyone has two sets of genetic information. NF is caused by an abnormal gene that dominates the normal gene. As a result, each child in this family has a 50 percent chance of inheriting their mother's abnormal gene. This is called dominant inheritance.