Neurofibromatosis-1

Definition

Neurofibromatosis-1 is an inherited disorder in which nerve tissue tumors (neurofibromas) form in the skin, bottom layer of skin (subcutaneous tissue), and nerves from the brain (cranial nerves) and spinal cord (spinal root nerves).

Alternative Names

NF1; Von Recklinghausen neurofibromatosis

Causes

NF1 is an inherited disease. If either parent has NF1, each of their children has a 50% chance of having the disease.

NF1 also appears in families with no previous history of the condition, as a result of a new gene change (mutation) in the sperm or egg. NF1 is caused by abnormalities in a gene for a protein called neurofibromin.

Symptoms

Neurofibromatosis causes unchecked growth of tissue along the nerves. This can put pressure on affected nerves and cause pain, severe nerve damage, and loss of function in the area served by the nerve. Problems with sensation or movement can occur, depending on the nerves affected.

The condition can be very different from person to person, even among people in the same family who have the NF1 gene.

The "coffee-with-milk" (caf-au-lait) spots are the hallmark symptom of neurofibromatosis. Although many healthy people have 1 or 2 small caf-au-lait spots, adults with 6 or more spots greater than 1.5 cm in diameter are likely to have neurofibromatosis. In most people with the condition, these spots may be the only symptom.

Other symptoms may include:

• Blindness
• Convulsions
• Freckles in the underarm or groin
• Large, soft tumors called plexiform neurofibromas, which may have a dark color and may spread under the surface of the skin
• Pain (from affected peripheral nerves)
• Small, rubbery tumors of the skin called nodular neurofibromas

Exams and Tests

Diagnosis is made by a doctor familiar with NF1, including a neurologist, geneticist, dermatologist, or developmental pediatrician. The diagnosis will usually be made based on the unique symptoms and signs of neurofibromatosis.

Signs include:

• Colored, raised spots (Lisch nodules) on the colored part (iris) of the eye
• Fracture of the long bones of the leg in early childhood
• Freckling in the armpits, groin, or underneath the breast in women
• Large tumors under the skin (plexiform neurofibromas), which can affect the appearance and put pressure on nearby nerves or organs
• Many soft tumors on the skin or deeper in the body
• Mild cognitive impairment, attention deficit hyperactivity disorder, learning disorders
• Soft nodules under the skin

Tests may include:

• Eye exam by an ophthalmologist familiar with NF1
• Genetic tests to find a change (mutation) in the neurofibromin gene
• MRI of the affected site
• Other specific tests for complications

Treatment

There is no specific treatment for neurofibromatosis. Tumors that cause pain or loss of function may be removed. Tumors that have grown quickly should be removed promptly as they may become cancerous (malignant). Experimental treatments for severe tumors are under investigation.

Some children with learning disorders may need special schooling.

Support Groups

For more information and resources, contact the National Neurofibromatosis Foundation.

Outlook (Prognosis)

If there are no complications, the life expectancy of people with neurofibromatosis is almost normal. With the right education and job expectations, people with neurofibromatosis can live a normal life.

Although mental impairment is generally mild, NF1 is a known cause of attention deficit hyperactivity disorder in a small number of patients. Learning disabilities are a common problem.

Some people are treated differently because they have hundreds of tumors on their skin.

Patients with neurofibromatosis have an increased chance of developing severe tumors. In rare cases, these can shorten a person's lifespan.

Possible Complications

• Attention deficit hyperactivity disorder (ADHD)
• Blindness caused by a tumor in an optic nerve (optic glioma)
• Break in the leg bones that does not heal well
• Cancerous tumors
• Loss of function in nerves that a neurofibroma has put pressure on over the long term
• Pheochromocytoma, which causes very high blood pressure
• Regrowth of NF tumors
• Scoliosis, or curvature of the spine
• Tumors of the face, skin, and other exposed areas

When to Contact a Medical Professional

Call your health care provider if:

• You notice coffee-with-milk colored spots on your child's skin or any of the signs listed here.
• You have a family history of neurofibromatosis and are planning to have children, or would like to have your child examined.

Prevention

Genetic counseling is recommended for anyone with a family history of neurofibromatosis.

Annual eye exams are strongly recommended.

References

Ferner RE. Neurofibromatosis 1 and neurofibromatosis 2: a twenty first century perspective. Lancet Neurol. 2007;6:340-351.

Haslam RHA. Neurocutaneous Syndromes. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelston Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 596.