Neurofibromatosis Type 2
What Is It?
Neurofibromatosis type 2 (NF 2) is one of the 2 most common general types of neurofibromatosis
. It is a genetic disorder that predisposes patients to certain types of nervous system tumors. It is less common that neurofibromatosis type 1 and occurs in about 1 in 60,000 people. While about half of patients inherit the mutated gene responsible for the disease from a parent, about half can also be born with the mutation de novo
, meaning that it is a newly acquired mutation that was not present in either parent. In the familial form, the mutated gene is autosomal dominant, meaning that one must only acquire 1 copy of the faulty gene to have the disease.
What Types of Symptoms Are Typical?
Although the genetic mutations associated with neurofibromatosis type 2 can express themselves differently in different individuals, there are some common manifestations of the disease.
While neurofibromatosis type 1 commonly presents with skin tumors, this is not seen in NF 2. More commonly, NF 2 patients have a propensity to grow a particular type of nervous system tumor called a schwannoma. While they can occur on other nerves, these are relatively common on the vestibular nerve which carries information about balance and equilibrium from the organs in the inner ear. This is called the 8th cranial nerve (the other division of the 8th nerve also carries sensory information about hearing from the inner ears). These vestibular schwannomas (or sometimes also called acoustic neuromas) are relatively rare in the general population. However, in individuals with neurofibromatosis type II they are common and in fact bilateral (on both sides) vestibular schwannomas alone can usually be diagnostic of NF 2. These tumors most commonly present with symptoms such as headache, hearing loss and/or tinnitus (ringing in the ears) on the side of the tumor.
Other types of tumors in tissues associated with the nervous system are also more common in these patients, most commonly other benign tumors such as meningiomas and ependymomas. The location of these types of tumors can vary so the specific symptoms that a patient will experience can vary greatly depending on which parts of the nervous system are affected.
How Is The Diagnosis Typically Made?
Genetic blood testing can confirm the genetic mutation associated with NF 2 if it is suspected. However, in those patients who do not have parents with the disease, the diagnosis may occasionally first be made only when the patient begins experiencing symptoms related to tumors. If these are frequent or occur in a pattern that is unlikely in the general population (such as bilateral vestibular schwannomas) it may suggest the diagnosis of NF 2.
Further work-up and evaluation of patients with neurofibromatosis includes imaging studies such as CT scans and/or MRI scans to identify tumors.
What Are Some Common Treatments?
While the actual genetic disease of neurofibromatosis type 2 is not curable, treatment can be offered to control symptoms related to the benign tumors that develop. While they are generally benign, these tumors can cause significant problems because of their proximity to normal nervous system structures which can be compressed or otherwise damaged by the growing tumor. Treatment of each tumor depends on several factors including symptoms, size and location of the tumor. Surgery and/or radiation treatments may be offered as options for tumor treatment.
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This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.