Neurofibromatosis: The most common genetic disorder

October 30, 2019 Swedish Neuroscience Team

NF causes tumors to form along the nerves affecting the nervous system and many other parts of the body. Learn who’s at risk.


A diagnosis of neurofibromatosis can be overwhelming, especially if you’ve never heard of it. You may have questions about the disorder, how to manage it and what’s next. Although a NF diagnosis can be a lot to digest, it's important to remember that patients and families are not alone. 

Neurofibromatosis is a genetic disorder of the nervous system where growths or tumors form along the nerves in the body. There are two different types – NF1 and NF2 – which are linked to different gene mutations and have very different manifestations.

We sat down with John W. Henson, M.D., neurologist and director at the new Swedish Neurofibromatosis Center to learn more about these debilitating disorders, who’s at risk and the treatment options. 

What are NF1 and NF2?

Neurofibromatosis cause excessive growth of nerve cells as well as some other cell types.

  • NF1 causes tumors along the peripheral nerves (outside the brain and spinal cord) and can lead to weakness, pain, vision problems, difficulty breathing, increased risk of high blood pressure and learning and thinking challenges. Nerve tumors under the skin make this disorder visible to the patient and others.
  • NF2 causes tumors along nerves that cause partial or complete hearing loss, facial nerve damage, and meningiomas, which are tumors of the brain’s covering. NF2 is not visible to the patient or others.

“NF1 is quite common,” says Dr. Henson, “occurring in one out of every 3,000 people. It affects men and women equally.” Half of patients with the disorder may be the first one in their family to be diagnosed, due to a new mutation in the NF1 gene.

NF2 is ten times less common than NF1, affecting about 1 in 30,000 people. Tumors often develop on the lining and nerves of the brain, spine and both ears.

“Although these tumors are noncancerous, they can be life-threatening, so ongoing surveillance and treatment is important,” says Dr. Henson.

What causes neurofibromatosis?

NF is caused by a mutation in a specific gene, the NF1 or NF2 gene. In about 50 percent of cases, NF mutations are inherited from a parent. In other cases, it’s caused by a new change (mutation) in the gene at the time of conception. “Once you have NF1 or NF2, the chance of a child inheriting it is 50 percent,” says Dr. Henson. For this reason, if you have the gene mutation in your family, it is critical to talk to an expert about genetic testing and family planning.

What are the complications associated with NF1 and NF2?

“Most patients will have complications because of tumor growth,” says Dr. Henson. “The neurofibromas on the nerves disrupt the function of the nerve or put pressure on nearby body parts,” says Dr. Henson. The tumors become large and cause disabling neurological conditions such as pain, motor dysfunction and disfigurement.”

There are other complications associated with NF1 and NF2 as well, including cancerous growths. For instance, the risk of breast cancer is three times higher than normal in women with NF1 between the ages of 30 and 50 years. “In women with NF1, for instance, we need to aggressively screen for breast cancer,” says Dr. Henson.

“Unfortunately, this disorder can reduce life expectancy by 15 or more years. The goal of the Swedish Neurofibromatosis Center is to give patients those 15 years back.”



Some people will experience mild symptoms of NF1, while others have more severe symptoms. These can affect different areas of the body and may include:

  • Brown skin spots called café au lait spots, and freckles under the arms and in the groin, for example.
  • Visible bumps (neurofibromas) on or under the skin, and small bumps on the colored part of the eye.
  • Pain or weakness from tumor growth on a nerve in the back, arms or legs.
  • Optic glioma, a tumor that develops in the cells around the optic nerve.
  • Small stature affects about 30 percent of people with NF1, and scoliosis (abnormal curvature of the spine) occurs in about 20 percent of NF1 patients.


Most people with NF2 develop symptoms while in their late teen and early adult years. The most common symptoms include:

  • Gradual hearing loss in one ear
  • Numbness of one side of the face
  • Facial weakness on one side
  • Vision loss
  • Difficulty with balance

Diagnosis and treatment

Because some of the largest neurofibromas form deep in the body, they’re not visible during a physical exam. A whole-body MRI allows an accurate assessment of the number of tumors and their size, placement, type and changes over time.

“The availability of breakthrough drug treatments such as MEK inhibitors is very good news for patients with neurofibromatosis. Sometimes we can operate on these tumors or rarely, administer radiation,” says Dr. Henson.

The Swedish Neurofibromatosis Center

The new Swedish Neurofibromatosis Center has a multidisciplinary team that provides care for the health issues that NF patients might develop. Clinics are held on Tuesdays, although patients can be seen any day based on need. The center focuses on patients age 18 years and older although older teenagers can be seen too.

These disorders are lifelong, and support is critical. “We always encourage our patients and family members to take care of themselves,” says Dr. Henson. “It may be overwhelming, but we’re here to help guide patients and families through the journey.”

 Find a doctor

If you have neurofibromatosis or a family history of the disorder, you can find a doctor at the Swedish Neurofibromatosis Center. Patients with other tumor genetic syndromes, including von Hippel-Lindau, tuberous sclerosis, Sturge-Weber, Turcot syndrome and Cowden syndrome are also seen in the specialty clinic. Many different subspecialties such as medical oncology, neurology, orthopedics and social services are also offered.

Working to give patients 15 years back #livingwithNF1 or #livingwithNF2 @swedish


NF Registry

Are you predisposed to these genetic diseases?

This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

About the Author

From deep brain stimulation to focused ultrasound to pediatric neurology, The Swedish Neuroscience Team is recognized as national experts to help people address a wide array of neurological conditions. Our goal is to provide useful and helpful advice and tips on non-surgical and surgical options to treat any disease of the mind.

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