Neurofibromatosis Type 2 is a genetic condition that mainly affects the nervous system. People with Neurofibromatosis Type 2 are at increased risk to develop tumors within their nerves. The most common type of tumor in people with Neurofibromatosis Type 2 is vestibular schwannoma (also known as acoustic neuroma). Vestibular schwannomas develop along the nerve that carries information from the inner ear to the brain (the auditory nerve). In people with Neurofibromatosis Type 2, vestibular schwannomas usually develop on both auditory nerves at an average age of 18 to 24 years. Almost all people with Neurofibromatosis Type 2 will develop bilateral (both-sided) vestibular schwannomas by 30 years old.
Tumors in other parts of the nervous system can also develop. These include:
- Meningiomas, tumors that form on the membranes surrounding the brain and spinal cord
- Ependymomas, tumors that form in fluid-producing cells of the brain or spinal cord
- Astrocytomas, tumors that form in supportive tissue in the brain or spinal cord
- Retinal hamartomas, tumors that form in the back of the eye
Cataracts and other eye problems are also common in people with Neurofibromatosis Type 2.
Neurofibromatosis Type 2 is hereditary, which means it can be passed from parents to their children. How severe the signs and symptoms of this condition are vary between families. However, people with Neurofibromatosis Type 2 who are in the same family often have a similar disease course.
Neurofibromatosis Type 2 is caused by changes in a gene known as NF2. Genes carry information telling cells in the body how to work. The NF2 gene helps to control how and when cells grow, divide, and die.
People without Neurofibromatosis Type 2 carry two working copies of the NF2 gene in their cells. One copy of NF2 is inherited from each parent. In most people with Neurofibromatosis Type 2, cells carry one working copy of NF2 and one copy that is changed. This change causes the gene to not work right. It is called an NF2 variant.
About half of children with Neurofibromatosis Type 2 inherit the NF2 gene variant from a parent who also has the syndrome. The other half of children with Neurofibromatosis Type 2 have a new NF2 variant that did not come from a parent. These children have no history of the syndrome in their family. In these cases, the change either happened in an egg or sperm cell when the child was formed or in one of the child’s cells during pregnancy. These children are the first in their families to have Neurofibromatosis Type 2. No matter how they acquired the NF2 variant, people with Neurofibromatosis Type 2 have a 50% (or 1 in 2) chance of passing it on to their children.
About 25–30% of people with Neurofibromatosis Type 2 without a family history of it have mosaic type neurofibromatosis 2 (sometimes called segmental neurofibromatosis 2). This means that the person has two different sets of cells that make up the body. One set contains two working copies of the NF2 gene. These cells are normal. The other set of cells contains one working and one non-working NF2 gene. These cells are abnormal. With mosaic, it is not possible to predict the exact risk of passing the NF2 variant on to future children. The risk is up to 50% (or a 1 in 2) chance of passing the NF2 variant onto each child.
As people with Neurofibromatosis Type 2 get older, the remaining working copy of NF2 often becomes changed in some of their cells. When both copies of the gene are changed, tumors can develop. Researchers believe this is why people with Neurofibromatosis Type 2 have a higher risk of developing tumors than people who do not have this condition.
A doctor may suspect this diagnosis after looking at a person’s medical or family history. In most cases, a doctor or genetic counselor will ask questions about the person’s health and the health of other family members. Read more about genetic counseling and genetic testing.
Diagnosing this syndrome is usually done by sequencing the NF2 gene to find variants (gene changes).
Genetic testing does not always find a variant that is responsible for the syndrome. A person can still have the syndrome even if no variants in these genes are found. This syndrome can be diagnosed without genetic testing based on clinical information.
For a person without a known family history of Neurofibromatosis Type 2, any one of the following confirms a diagnosis of the condition:
- Bilateral (both-sided) vestibular schwannoma tumors
- Unilateral (one-sided) vestibular schwannoma tumor, plus any two of the following:
- Meningioma
- Schwannoma
- Glioma
- Neurofibroma
- Cataract
- Multiple meningiomas, plus one of the following:
- Unilateral vestibular schwannoma
- Any two of these: schwannoma, glioma, neurofibroma or cataract
For a person with a known family history of Neurofibromatosis Type 2, any one of the following confirms a diagnosis of the condition:
- Vestibular schwannoma (unilateral or bilateral)
- Any two of these: meningioma, schwannoma, glioma, neurofibroma or cataract
Nearly all people with Neurofibromatosis Type 2 develop some type of tumor within the nervous system. The tumors usually develop along nerves in the brain and spinal cord, and sometimes in other parts of the body. The tumors are almost always non-cancerous, but often they must be removed because they can cause problems.
The tumors that can develop in Neurofibromatosis Type 2 and their lifetime risk are as follows:
- Vestibular schwannoma (unilateral or bilateral): 95%
- Meningioma: 80%
- Spinal tumors (schwannomas, astrocytomas, and epindymomas): 66%
- Retinal hamartoma: 33%
In some cases, the tumors may change and behave like cancers, but the risk of this is low. Doctors do not know what the exact risk of the tumors becoming cancerous is because it only happens very rarely.
Cancer screening involves tests to check for cancer before symptoms occur. The goal is to find cancer at the earliest and most treatable stage. Guidelines for cancer screening are available online. Recommended screenings may change over time as doctors learn more about this syndrome, so these screening tests should be discussed with a health care provider who knows this syndrome well.
Other ideas to reduce the risk of cancer include:
- Eat a healthful diet with lots of fruits and vegetables
- Get regular exercise
- Avoid smoking or using tobacco products
- Avoid secondhand smoke
- Avoid excess sun exposure and always wear sunscreen, hat, and protective clothing when out in the sun
- Get medical attention for unusual or ongoing symptoms
Because of the medical concerns related to this syndrome, specialists in the following areas may need to assess a child with Neurofibromatosis Type 2:
- Neurology
- Audiology
- Ophthalmology
- Genetics Home Reference (ghr.nlm.nih.gov/condition/neurofibromatosis-type-2)
- Neurofibromatosis Network (www.nfnetwork.org)
- Children’s Tumor Foundation (www.ctf.org)
Other resources:
- Making Sense of Your Genes: A Guide to Genetic Counseling (www.ncbi.nlm.nih.gov/books/NBK115508/)
Adapted from educational materials developed by the St. Jude Children’s Research Hospital Cancer Predisposition Program