The National Institute of Neurological Disorders and Stroke (NINDS) defines neurofibromatosis as a group of “genetic disorders of the nervous system that primarily affect the development and growth of neural (nerve) cell tissues.” Neurofibromatosis is an autosomal dominant disorder, meaning that a child has a 50 percent chance of developing the disorder if one parent has it. Besides inheriting the neurofibromatosis gene, a patient can also have a genetic mutation that results in the disorder, and then pass it down through her children. Two types of neurofibromatosis exist—neurofibromatosis type one (NF1) and neurofibromatosis type two (NF2)—which affect different genes.
Neurofibromatosis Type One
NF1 is the most common type of neurofibromatosis, affecting one in every 3,000 to 4,000 people in the world, according to the Genetics Home Reference. This type of neurofibromatosis is caused by a mutation of the NF1 gene, which is responsible for making the neurofibromin protein. Neurofibromin produces supporting cells, like oligodendrocytes and Schwann cells, and also acts as a tumor suppressant. Since the mutation to the NF1 gene interferes in the mechanism of neurofibromin, the patient develops a type of tumor called a neurofibroma, a benign tumor the grows either on the skin or below it.
The National Institutes of Health (NIH) notes that the hallmark symptom of NF1 is café-au-lait spots on the skin, which are a milky coffee color, as its name implies. A patient with NF1 will have six or more of these spots, with each spot larger than 1.5 centimeters. The patient may also notice different types of tumors: large and soft ones (plexiform neurofibromas) or small and rubbery ones (nodular neurofibromas). Other symptoms of NF1 include pain, blindness, convulsions and freckles on the underarm or groin.
Neurofibromatosis Type Two
NF2 is the less common form of neurofibromatosis, affecting one in 25,000 people in the world, according to the Genetics Home Reference. The NF2 gene is mutated, which affects the merlin protein; the merlin protein produces Schwann cells, and is also a tumor suppressant. A patient with NF2 also has benign tumors, such as acoustic neuromas and vestibular schwannomas. As a result, the patient has hearing problems, such as ringing and noises in the ears and hearing loss, according to the NIH. Changes in vision can also occur, as well as cataracts at a younger age. The café-au-lait spots also occur in NF2. Other symptoms include balance problems, headaches and facial weakness.
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Elizabeth Stannard Gromisch received her bachelor’s of science degree in neuroscience from Trinity College in Hartford, CT in May 2009. She is the Hartford Women's Health Examiner and she writes about abuse on Suite 101.