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Guidelines for sites linking to mayoclinic.orgSymptoms may be limited to skin or eye markings or may include more serious complications. Which symptoms people with NF1 develop varies widely — even within families — but at least some symptoms are usually present by age 10 and may include:
Café au lait ("coffee with milk") spots on the skin usually appear in the first few years of a person's life and increase in number and size over time. They can occur on most parts of the body other than the scalp, palms of the hands and soles of the feet. They often increase in number during puberty and may darken with exposure to sunlight. While helpful in diagnosing NF1, these spots don't cause health problems.
Freckles may appear in places not typically exposed to the sun, such as the underarm (axillary freckling) or groin (inguinal freckling). Freckles may not develop until puberty. They are not a health problem, though they may sometimes itch.
Lisch nodules — pigmented bumps on the eye's iris (also called iris hamartomas) — can help diagnose NF1 but don't affect vision. They often don't appear until later in childhood.
Neurofibromas (sometimes called fibroneuromas) are slow-growing benign tumors that can develop along nerves almost anywhere in the body. They often appear as small, fleshy, pea-sized nodules within the skin, called dermal or cutaneous neurofibromas. People with NF1 may develop a few or many. People who do not have NF1 sometimes have neurofibromas, though usually no more than several.
Plexiform neurofibromas are larger, more ropelike tumors that can wrap in and around nerves, blood vessels and other structures almost anywhere in the body.
Neurofibromas can affect appearance, cause pain or affect function, depending on their location and size. Neurofibromas that affect large nerves or the spinal cord are the most likely to cause serious problems.
Pheochromocytomas (tumors of the adrenal gland) also sometimes occur in people with NF1 and can cause high blood pressure (as can a neurofibroma that presses on the kidneys or renal artery).
In rare instances, a neurofibroma (usually a plexiform neurofibroma) mutates into a malignant tumor (called a neurofibrosarcoma, malignant schwannoma, neurogenic sarcoma, or malignant peripheral nerve sheath tumor).
Optic pathway gliomas (also called optic nerve gliomas or juvenile pilocytic astrocytomas) occur in about 30 percent of people with NF1. The optic pathway includes the optic nerve, which sends messages from the eye to the brain, and the optic chiasm, where the optic nerves from each eye cross before entering the two hemispheres of the brain. A glioma is a tumor that arises from glial cells (supporting cells of the nervous system).
Optic pathway gliomas usually develop by age 10, but sometimes may not be detected until later. While many people with optic gliomas have no symptoms, signs might include:
"Unidentified bright objects" (UBOs) often show up on MRI brain scans of people with NF1. Their significance is not understood.
Weakness of the dura (covering of the brain and spinal cord) is associated with NF1 and can sometimes cause problems such as a meningocele (herniation of the spinal cord through the vertebrae) or hydrocephalus (excess fluid accumulation in the brain).
Abnormal development of the temple bone (sphenoid dyplasia) occurs in about 1 percent of people with NF1 and can lead to eye displacement or herniation of part of the brain.
Thinning of the tibia in the shin or the radius in the arm is found at birth in about 1 percent of people with NF1. It can result in pseudarthrosis, meaning "false joint," because unhealed fractures resulting from bone loss can cause the bone to bow, bend and eventually break. It usually only occurs on one side of the body, and males are more likely than females to have the problem.
About 20 percent to 30 percent of people with NF1 have scoliosis (abnormal curvature of the spine) or khyphosis (a hunched posture).
Neurofibromas near bones can cause them to erode or to grow irregularly.
Up to one half of children with NF1 may have learning disabilities involving reading, writing, and neuromotor skills that may be accompanied by attention deficit/hyperactivity disorder.
Mental retardation occurs in fewer than 10 percent of people with NF1.
Unlike other symptoms of NF1, cognitive problems are not progressive; they don't get worse with aging.
People with NF1 usually have a large head circumference relative to height and weight and are often shorter than average height. High blood pressure, seizures and hydrocephalus also occur more often in people with NF1 than in the general population.
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