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| DiseaseID |
HGD7 |
| Genetic
Disorder |
Neurofibromatosis 2
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| Gene
Name |
The NF2 gene 'tumor- suppressor gene' |
| Description |
Neurofibromatosis, type 2, (NF-2) is a rare inherited disorder characterized by the development of benign tumors on both auditory nerves (acoustic neuromas). The disease is also characterized by the development of malignant central nervous system tumors as well. . NF2, also referred to as bilateral acoustic NF, central NF or vestibular NF, occurs in approximately 1 in 40,000 births
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| Symptoms |
Symptoms of NF2 include:
Balance problems Cataracts at a young age Changes in vision Coffee-colored marks on the skin Facial weakness Headaches Hearing loss Ringing and noises in the ears
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| Causes |
NF2 is passed down through families in an autosomal dominant fashion. This means that if one parent has NF2, any child of that parent has a 50-50 chance of having it.
The main risk factor is having a family history of the condition. |
| Diagnosis |
Signs include:
• Brain and spinal tumors
• Hearing-related (acoustic) tumors
• Skin tumors
Tests include:
• Genetic testing
• Medical history
• MRI
• Physical examination
For NF2, doctors will pay close attention to hearing loss. Hearing tests as well as imaging tests are used to look for tumors in and around the auditory nerves, the spinal cord or the brain. Audiometry and brainstem auditory evoked response tests can help determine whether the eighth cranial nerve is functioning properly. Family history of NF2 is also a key focal area for diagnosis.
Genetic testing is also used to diagnose NF2. Testing conducted before birth (prenatal) is helpful to identify individuals who have a family history of the disorder, but do not yet have the symptoms. Still, gene tests have no way of predicting the severity of NF1 or NF2. Genetic testing is performed by either direct gene mutation analysis and/or linkage analysis. Mutation analysis looks to identify the particular gene changes that cause NF. A linkage analysis is useful if the mutation analysis does not provide enough conclusive information. With at linkage analysis, blood tests from multiple family members are taken to track the chromosome that carry the disease-causing gene through two or more generations. Linkage testing is around 90 percent accurate in determining whether individuals have NF. Mutation analysis is 65 percent accurate for NF2.
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| Treatment |
Though there is no cure for NF2, there are ways to treat the effects the disease. Surgery may be helpful in removing tumors, though there is a risk of the tumors regenerating. For optic gliomas, treatment may include surgery and/or radiation. For scoliosis, treatment may include surgery or back braces. For symptoms associated with NF2, surgery may be a viable option, however not without complications that could result in additional loss of hearing or deafness. Hearing aids are ineffective when parts of the auditory nerve are removed. A breakthrough in treatment became available recently to NF2 patients, when the Food and Drug Administration approved an Auditory Brainstem Implant [fda.gov] for those who have parts of their auditory nerve removed and have suffered from subsequent hearing loss. The implant transmits sound signals to the brain directly and allows people to hear certain sounds and speech . Radiation treatment, may also help relieve symptoms associated with NF2. |
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