Neurofibromatosis type 1

Date Updated: 07/14/2026

Overview

Neurofibromatosis type 1 (NF1) is a genetic condition that causes changes in skin pigment and the growth of tumors on nerve tissue. Skin changes include flat, light brown spots and freckles in the armpits and groin. Tumors can grow anywhere in the nervous system, including the brain, spinal cord and nerves. NF1 is rare. About 1 in 2,500 children are born with the condition.

The tumors often are not cancerous. These are known as benign tumors. But sometimes they can become cancerous. Although symptoms often are mild, complications can occur. They may include trouble with learning, heart and blood vessel conditions, vision loss, and pain.

Treatment focuses on supporting healthy growth and development in children and managing complications in adults and children. If NF1 causes large tumors or tumors that press on a nerve, surgery can reduce symptoms. Medicines can treat tumors that grow along nerves, called plexiform neurofibromas.

Symptoms

Neurofibromatosis type 1 (NF1) usually is diagnosed during childhood. Symptoms are seen at birth or shortly afterward and almost always by age 10. Symptoms tend to be mild to moderate, but they can vary from person to person.

Symptoms include:

Flat, light brown spots on the skin, known as cafe au lait spots. These harmless spots are common in many people. But having more than six cafe au lait spots suggests NF1. They often are present at birth or appear during the first years of life. After childhood, new spots stop appearing.
Freckling in the armpits or groin area. Freckling often appears by ages 3 to 5. Freckles are smaller than cafe au lait spots and tend to occur in clusters in skin folds.
Tiny bumps on the iris of the eye, known as Lisch nodules. The iris is the colored part of the eye. These bumps can't easily be seen and don't affect vision.
Soft, pea-sized bumps on or under the skin called neurofibromas. These noncancerous tumors usually grow in or under the skin but also can grow inside the body. A growth that involves many nerves is called a plexiform neurofibroma. Plexiform neurofibromas can cause visible changes on the face. Neurofibromas may increase in number with age.
Bone changes. Changes in bone development and low bone mineral density can cause bones to form in an irregular way. People with NF1 may have a curved spine, known as scoliosis, or a bowed lower leg.
Tumor on the nerve that connects the eye to the brain, called an optic pathway glioma. This tumor usually appears by age 6. The tumor rarely appears in late childhood and among teenagers, and almost never in adults.
Learning disabilities. It's common for children with NF1 to have some trouble with learning. Often there is a specific learning disability, such as trouble with reading or math. Attention-deficit/hyperactivity disorder (ADHD) and speech delay also are common.
Larger than average head size. People with NF1 tend to have a larger than average head size due to increased brain volume.
Short stature. People who have NF1 often are below average in height.

When to see a doctor

See a healthcare professional if you or your child has symptoms of neurofibromatosis type 1. The tumors are often not cancerous and are slow growing, but complications can be managed. If you or your child has a plexiform neurofibroma, a medicine is available to treat it.

Causes

Neurofibromatosis type 1 is caused by an altered gene that either is passed down by a parent or occurs at conception.

The NF1 gene is located on chromosome 17. This gene produces a protein called neurofibromin that helps regulate cell growth. When the gene is altered, it causes a loss of neurofibromin. This allows cells to multiply.

Risk factors

The biggest risk factor for neurofibromatosis type 1 (NF1) is a family history. For about half of people who have NF1, the disease was passed down from a parent. People who have NF1 and whose relatives aren't affected are likely to have a new change to a gene.

NF1 has an autosomal dominant inheritance pattern. This means that any child of a parent who is affected by the disease has a 50% chance of having the altered gene. However, it's possible to have NF1 without a family history of the condition.

Complications

Complications of neurofibromatosis type 1 (NF1) vary, even within the same family. Generally, complications occur when tumors affect nerve tissue or press on internal organs.

Complications of NF1 include:

Neurological symptoms. Trouble with learning and thinking are the most common neurological symptoms related to NF1. Less common complications include epilepsy and the buildup of excess fluid in the brain.
Worries about appearance. Visible signs of NF1 can include widespread cafe au lait spots, many neurofibromas on the face or large neurofibromas. In some people this can cause anxiety and emotional distress, even if they're not medically serious.
Skeletal symptoms. Some people have bones that didn't form as usual. This can cause bowing of the legs and fractures that sometimes don't heal. NF1 can cause curvature of the spine, known as scoliosis, that may need bracing or surgery. NF1 also is linked to lower bone mineral density, which increases the risk of weak bones, known as osteoporosis.
Changes in vision. Sometimes a tumor called an optic pathway glioma develops on the optic nerve. When this happens, it can affect vision.
Increase in symptoms during times of hormonal change. Hormonal changes during puberty or pregnancy might cause an increase in neurofibromas. Most people who have NF1 have healthy pregnancies but will likely need monitoring by an obstetrician who is familiar with NF1.
Cardiovascular symptoms. People who have NF1 have an increased risk of high blood pressure and may develop blood vessel conditions.
Trouble breathing. Rarely, plexiform neurofibromas can put pressure on the airway.
Cancer. Some people who have NF1 may develop cancerous tumors. These usually arise from neurofibromas under the skin or from plexiform neurofibromas. People who have NF1 also have a higher risk of other forms of cancer. They include breast cancer, leukemia, brain tumors and some types of soft tissue cancer. Screening for breast cancer should begin earlier, at age 30, for women with NF1 compared with the general population.
Benign adrenal gland tumor, known as a pheochromocytoma. This noncancerous tumor produces hormones that raise blood pressure. Surgery often is needed to remove the tumor.

Diagnosis

To diagnose neurofibromatosis type 1 (NF1), a healthcare professional begins with a review of your personal and family medical history and a physical exam.

Your child's skin is checked for cafe au lait spots, which can help diagnose NF1.

Other tests needed to diagnose NF1 may include:

Eye exam. An eye exam can reveal Lisch nodules and vision loss.
Imaging tests. X-rays, CT scans or MRI scans can help identify bone changes, tumors in the brain or spinal cord, and very small tumors. An MRI might be used to diagnose optic gliomas.
Genetic tests. Genetic testing for NF1 can help support the diagnosis. Genetic tests also can be done in pregnancy before a baby is born. Ask a member of your healthcare team about genetic counseling.

For a diagnosis of NF1, at least two symptoms of the condition must be present. A child who has only one symptom and no family history of NF1 is likely to be monitored for any other symptoms. A diagnosis of NF1 can be made by age 4.

Treatment

There is no cure for neurofibromatosis type 1 (NF1), but symptoms can be managed. Generally, the sooner someone is under the care of a specialist trained in treating NF1, the better the outcome.

Monitoring

If your child has NF1, often yearly age-appropriate checkups are recommended to:

Check your child's skin for new neurofibromas or changes in existing ones.
Check for signs of high blood pressure.
Check your child's growth and development. This includes measuring height, weight and head circumference to compare to growth charts for children who have NF1.
Look for signs of early puberty.
Look for any skeletal changes.
Check your child's learning development and progress in school.
Get a complete eye exam.

Adults with NF1 need screening tests that may include:

Annual mammograms starting at age 30 to screen for breast cancer. Your healthcare professional may recommend a contrast-enhanced mammogram.
Screenings for high blood pressure and related conditions.
Yearly screenings for a curved spine, known as scoliosis.
Imaging of plexiform neurofibromas, especially if there are symptoms, such as pain.
Tests for a rare tumor that grows in an adrenal gland, known as a pheochromocytoma.
Screenings for depression, attention-deficit/hyperactivity disorder (ADHD) and changes in thinking ability, known as cognitive impairment.

Adults who want to start a family can talk to a genetic counselor about the risks of passing the disease to a child.

Contact your healthcare team right away if you notice any changes in symptoms between visits. Many complications of NF1 can be treated effectively if therapy starts early.

Medications

Medicines have been approved by the U.S. Food and Drug Administration to treat tumors that grow in multiple nerves, known as plexiform neurofibromas. Selumetinib (Koselugo) has been approved to treat the tumors in children. Mirdametinib (Gomekli) has been approved to treat plexiform neurofibromas in both children and adults. The medicines can shrink the size of a tumor. Clinical trials of similar medicines are currently underway.

Surgery and other procedures

Surgery to remove tumors may be needed to treat serious symptoms or complications of NF1. Symptoms can be relieved by removing all or part of tumors that are compressing nearby tissue or damaging organs.

Cancer treatment

Cancers related to NF1 are treated with standard cancer therapies, such as surgery, chemotherapy and radiation therapy. Early diagnosis and treatment are the most important factors for a good outcome.

Potential future treatments

Researchers are testing gene therapies for neurofibromatosis type 1 (NF1). Potential new treatments could include replacing the NF1 gene to restore the function of the protein that affects cell growth, called neurofibromin.

Coping and support

Living with neurofibromatosis type 1 (NF1) can be challenging. But many people live healthy lives with few, if any, complications.

To help you cope:

Find a healthcare professional you can trust and who can coordinate your care with other specialists. If you're a parent of a child with NF1, the Children's Tumor Foundation has an online tool to help you find a specialist in your area.
Join a support group for people with NF1. You might look for support groups for adults or children who have NF1, attention-deficit/hyperactivity disorder (ADHD), special needs or lifelong illnesses. If you're a parent, it may help to seek out other parents caring for children with NF1.
Accept help for daily needs, if needed, such as cooking or cleaning.
If your child has NF1 and has a learning disability, seek academic support.

Preparing for an appointment

You may be referred to a doctor who specializes in brain and nervous system conditions, known as a neurologist.

It's a good idea to be well prepared for your appointment. Here's some information to help you get ready and know what to expect.

What you can do

Write down a list of concerns, making a note of when you first noticed them.
Bring a complete medical and family history with you if your healthcare professional doesn't already have it.
Write down key personal information, including any major stresses or recent life changes.
Make a list of all medicines, vitamins or supplements that you or your child is taking.
Bring photographs of any family members — living or deceased — who may have had similar symptoms.
Write down questions to ask your healthcare professional.

Preparing a list of questions ahead of time can help you make the most of your time during your appointment. List your questions from most important to least important in case time runs out. For neurofibromatosis type 1, some basic questions to ask include:

Do you suspect neurofibromatosis type 1?
What tests do you recommend?
What treatments are available?
How should the condition be monitored for changes?

In addition to the questions that you've prepared, don't hesitate to ask others that come up during your appointment.

What to expect from your doctor

You'll likely to be asked a number of questions. Being ready to answer them may allow time later to cover other points you want to address. Your healthcare professional may ask:

When did you first notice symptoms? Have they changed over time?
Is there a family history of neurofibromatosis type 1?