Neurofibromatosis, type 1 (NF1) is a genetic condition that can cause certain pigment (color) changes on the skin, an increased risk for certain types of cancer, and benign tumors in the skin, brain, and other parts of the body. The signs of NF1 can usually be found in childhood, and the first signs that are found are often the skin pigment changes, which can sometimes be very subtle. As people with NF1 get older, their chance to develop the tumors and cancer increase.
Mutations (or changes) in the NF1 gene causes NF1, and are inherited in an autosomal dominant pattern, meaning that children of a mutation carrier each have a 50% risk to inherit the mutation and associated cancer risks. Notably, women and men both have the NF1 genes and have the same chances to inherit and pass down mutations in these genes. Therefore, both sides of the family are important when assessing inherited risk. About 50% (or 1 in 2 people) with NF1 will also have a parent with NF1. The other 50% have no family history and will be the first ones in their family with this condition.
Individuals with NF1 are also at an increased risk to have scoliosis (curvature of the spine) or other bone abnormalities, as well as other tumors of the gastrointestinal tract or central nervous system. About half of people with NF1 also have learning disabilities.
If you or your family meet any of the above criteria, a meeting with a pediatric or adult genetics specialist can be helpful to further determine if someone has NF1.
The overall lifetime risk for cancer in NF1 is approximately 60%, which includes an increased risk for breast cancer, and certain gastrointestinal and central nervous system cancers. Studies have shown that women with NF1 have an elevated risk to develop breast cancer before the age of 50. After age 50, the risk to develop breast cancer returns to the level of other women in the general population.
NF1 is diagnosed by detailed physical examination (usually done by a geneticist) and family history. The geneticist can look for the signs of NF1 during the examination and usually can determine if someone has NF1 or not based on that physical exam.
Genetic testing for NF1 is not always needed, as it can be diagnosed via physical exam by a genetics specialist. There are some instances where genetic testing can be helpful:
If genetic testing is being done, there are a couple of different approaches:
If you (or your child) are diagnosed with NF1, it is recommended to establish care with a neurofibromatosis specialist who will evaluate and manage for any neurologic or other complications associated with this condition, including risk for NF1-associated cancers.
The National Comprehensive Cancer Network (NCCN) recommends that women who have a diagnosis of NF1 should start annual mammogram screening at age 30, and should consider annual breast MRIs between the ages of 30 and 50. It is important to note the possibility that benign neurofibromas within the breast tissue may cause false- positive results on MRI. There is not currently any data or evidence to recommend risk-reducing mastectomies for women with NF1, but it may be considered on a case-by-case basis depending on family history. More personalized recommendations will take into account your personal and family history and should be discussed with your provider.