by Kimberly Allen, RN
Neurofibromatosis or NF are a group of genetic disorders that alter the cell growth in your nervous system. They are all considered autosomal dominant disorders. Neurofibromatosis affects over 2 million people worldwide and approximately 91,000 new cases are diagnosed every year in the US which makes NF more prevalent that cystic fibrosis and Duchenne muscular dystrophy as well as Huntington’s disease combined. Yet despite these figures neurofibromatosis is considered rare.
Neurofibromatosis is a condition that causes tumors to develop on nerve tissue. The tumors of neurofibromatosis can form anywhere in your nervous system from your brain and spinal cord to the smallest peripheral nerves. Most of these tumors tend to be non-cancerous however, some can become cancerous. Neurofibromatosis is caused by a genetic mutation. In most cases there is a family history if neurofibromatosis however, in at least 30% of the cases there is no family history of neurofibromatosis, it develops because of a spontaneous mutation. Also, once the mutation has occurred the mutant gen can be inherited by future generations.
There are now 3 recognized types of neurofibromatosis, neurofibromatosis type I, neurofibromatosis type II and recently added is Schwanomatosis. Each type is a completely different condition cased by mutations in different genes.
Neurofibromatosis type I is by far the most common of the three. It is caused by a mutated gene on chromosome 17. Under normal conditions this gene produces neurofibromin which is a protein that helps to regulate cell growth. When you are born with the mutated gene there is less neurofibromin therefore the cells are allowed to grow out of control. NF I is classified as a syndrome which simply means there are several symptoms that occur together. NF I can range from very mild to severe. For the majority of people with NF I there is no significant health problems. NF I is characterized by patches of light brown or tan skin called “cafe au lait spots”. There frequently are soft, pink growths known as neurofibromas on or under your skin. Some people experience enlarged as well as deformity of bones even a condition known as scoliosis, which is curvature of the spine. In some people these tumors or neurofibromas develop in the brain as well as on the cranial nerves and spinal cord. Also, over 50% of children born with NF I have learning disabilities.
Neuroifibromatosis type II also known as bilateral acoustic NF or BAN is not nearly as common as NF I. The gene mutation for NF II occurs on chromosome 22. Chromosome 22 is responsible for producing a protein known as merlin. A mutation in this gene causes there to be less merlin which in turn allows the cells to grow out of control. In NF II multiple tumors develop on the cranial and spinal nerves. These tumors affect both of the auditory nerves which leads to hearing loss. The hearing loss is frequently the first symptom of NF II noticed and it usually manifests in the teens or early 20’s.
Schwanomatosis is thought to be the rarest of the three was recently classified as a form of NF. It has been linked to a mutation of the SMARCB1 gene which is on chromosome 22. Schwanomatosis is rarely diagnosed before you are 20 to 30 years of age. In this type of NF painful tumors form on the cranial and spinal nerves as well as the peripheral nerves. However, these tumors do not affect the 8th cranial nerve, which is the nerve that transmits information on sound and balance from the inner ear to the brain.
There is no cure for any of the types of neurofibromatosis. Treatment is focused on treating your symptoms and preventing and/or treating complications. It’s important to find a doctor trained and experienced in treating neurofibromatosis. The earlier you or your child sees a specialist and a treatment plan is developed the better the prognosis. If the symptoms are mild the doctor may recommend frequent check ups to assess and monitor for any changes in you or your child’s condition. If the tumors are large and damaging the surrounding organs and tissue the doctor may recommend surgery to remove the tumors. Some people with NF II may be eligible for implants such as the auditory brainstem implant or cochlear implants to improve their hearing.
Kimberly Allen is a registered nurse with an AND in nursing. She has worked in ACF, LCF and psychiatric facilities, although she spent most of her career as a home health expert. She is now a regular contributor to HealthAndFitnessTalk.com, dispensing advice and knowledge about medical issues and questions. You can reach her with any comments or questions at firstname.lastname@example.org.