Neurofibromatosis (NF) is characterized by the tumors that develop in the nerve tissues anywhere in the body including the spinal cord and the brain. These tumors are mostly benign (noncancerous) but sometimes has the potential to become cancerous. There are three types of neurofibromatosis; NF1, NF2 and schwannomatosis. The most common forms of tumors related to this type include the vestibular schwannomas or acoustic neuromas which develop on the auditory nerve responsible for the transmission of information from the inner ear to the brain. The tumors of this type can also be found on other nerves in the body. The symptoms can become evident at any age although it usually appears during adolescence or in the twenties. NF2 is estimated to affect around 1 in 33,000 individuals globally.
Causes
This condition develops because of the genetic mutation identified in the gene NF2 which is responsible for the production of a protein known as merlin. This protein is produced in the nervous system, particularly in the neurons of the brain and the spinal cord. The protein merlin acts as a tumor suppressor meaning it prevents the cells from dividing and growing rapidly. The genetic mutation results in the production of a nonfunctional merlin protein which is not able to regulate the normal growth and the division of cells. This disorder is considered to be inherited in an autosomal dominant pattern meaning a single mutated copy of the gene in each cell can cause this condition.
Symptoms
The symptoms result from the tumors on the auditory nerves which can include ringing in the ears (tinnitus), problems with balance and progressive hearing loss. The other tumors of the central nervous system can include neurofibromas, low-grade gliomas, meningioma sans schwannomas. The affected individuals may also develop posterior capsular cataracts which can impair the vision. Additional symptoms can include café au lait spots on the skin, spasms of the facial muscles, muscle weakness, partial paralysis, impaired speech, difficulty swallowing and other neurological problems such as seizures.
Diagnosis
The diagnosis is based on the clinical evaluation, the symptoms evident, the history of the family and with various tests such as a CT scan and an MRI. A molecular genetic testing can help identify the mutation responsible for the development of the condition. The genetic testing can be considered particularly for those who have a positive family history of the disease.
Treatment
The treatment is based on the surgical removal of the tumors that are based on the size and its location. Radiation therapy may be optional for those who cannot undergo the surgical procedure. Other forms of treatments include providing symptomatic relief and supportive care. Regular monitoring may be required for those particularly at high risks such as an annual MRI and a regular hearing evaluation. Genetic counseling may be beneficial for some of the affected individuals and their family members.
