Neurofibromatoses are genetic disorders of the nervous system. Mainly, these disorders affect the growth and development of nerve cell tissue. The disorders are known as neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). NF1 is the more common type of neurofibromatosis. Schwannomatosis has recently been identified as a third and more rare type of neurofibromatosis, but little is known about it.
NF1, also called von Recklinghausen NF or peripheral NF, is characterized by multiple café au lait spots (patches of tan or light brown skin) and neurofibromas (soft, fleshy growths) on or under the skin. Enlargement and deformation of bones and curvature of the spine (scoliosis) may also occur. Occasionally, tumors may develop in the brain, on cranial nerves, or on the spinal cord. More than 50% of people with NF1 also have learning disabilities.
Dupuytren's contracture is an abnormal thickening and tightening of the normally elastic tissue beneath the skin of the palm and fingers. This tissue is called fascia. The fascia contains strands of fibers, like cords, that run from the palm upward into the fingers. In Dupuytren's contracture, these cords tighten, or contract, causing the fingers to curl forward. In severe cases, it can lead to crippling hand deformities.
NF2, also called bilateral acoustic NF (BAN), is much less common than NF1 and is characterized by multiple tumors on the cranial and spinal nerves. Tumors that affect both of the auditory nerves and hearing loss beginning in the teens or early twenties are generally the first symptom of NF2.
What Causes Neurofibromatosis?
Neurofibromatosis is often inherited (passed on by family members through our genes), but 30% to 50% of people newly diagnosed with the disorder have no family history of the condition, which can arise spontaneously through a mutation (change) in the genes. Once this change has taken place, the mutant gene can be passed on to future generations.