Neurofibromatosis type 1 may either be inherited in an autosomal dominant pattern or it may be due to a new gene mutation in an individual. The gene for neurofibromatosis type 1 is located on chromosome 17.
Symptoms
Neurofibromatosis type 1 is the most common type of neurofibromatosis. It occurs in about 1 in 4,000 births. Symptoms of NF1 include:
light brown spots (cafe-au-lait spots) on the skintumors around nerves (called neurofibromas)freckles in the armpits or in the groin areasgrowths on the iris of the eye (called Lisch nodules or iris hamartomas)tumors on the optic nerve of the eye (optic glioma)abnormal curving of the spine (scoliosis)malformation of other bones
Many children with NF1 have larger than normal head circumference and are shorter than average. Nearly 50% have speech problems, learning disabilities, seizures, or hyperactivity. Individuals with NF1 may also have headaches, heart defects, high blood pressure, or blood vessel disease (vasculopathy).
Diagnosis
The symptoms of NF1 are often present at birth or shortly after, and almost always are present by age 10 years. For children to be diagnosed with NF1, they must show at least two of the above symptoms. In addition to a physical examination, doctors may use special lamps to examine the skin for cafe-au-lait spots. In NF1, six or more of these spots are present, and they measure more than 5 mm in diameter in children or more than 15 mm in diameter in adolescents and adults. Magnetic resonance imaging (MRI), X-rays, computed tomography (CT) scans, and other tests may be done to look for neurofibromas and abnormal bones. Genetic testing by blood test can be done to detect defects in the NF1 gene.
Treatment
Doctors do not know how to stop the tumors from growing in neurofibromatosis. Surgery can be used to remove tumors that are causing pain or problems with vision or hearing. Chemical or radiation treatments may be used to reduce the size of tumors. In NF1, some bone malformations, such as scoliosis, can be treated with surgery or braces.
Other symptoms such as pain, headaches, or seizures can be managed with medications or other treatments.
