About Schwannomatosis
The New York Center for Rare Diseases supports the mission and guidelines of the Genetic and Rare Diseases Information Center (GARD). The following information is provided by the NIH.
Summary
Schwannomatosis is a rare form of neurofibromatosis that is primarily characterized by multiple schwannomas (benign tumors of the nervous system) in the absence of bilateral (affecting both sides) vestibular schwannomas. Signs and symptoms of the condition vary based on the size, location and number of schwannomas but may include pain; numbness; tingling; and/or weakness in the fingers and toes. Inherited forms of the disorder account for only 15 percent of all cases. In some of these families, Schwannomatosis is caused by changes in the SMARCB1 or LZTR1 genes; in other cases, the exact underlying cause is unknown. When inherited, the condition is passed down in an autosomal dominant manner with highly variable expressivity and reduced penetrance.
Causes
What Causes This Disease?
Genetic Mutations: Schwannomatosis is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these.
If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team.
Known Genetic Mutations: Schwannomatosis is caused by genetic mutations in the following known gene(s):
SMARCB1
Given these known genetic mutation(s), you may want to ask your health care team if genetic testing is right for you. Genetic tests are laboratory tests that use samples of blood, saliva, or other tissues to help identify changes in genes, chromosomes, or proteins. Genetic testing can help confirm or rule out a suspected genetic disease, or can provide other useful information to your health care team.
Can This Disease Be Passed Down From Parent to Child?
Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team.
There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD’s current data, this disease can be inherited in the following pattern(s):
Autosomal Dominant: Autosomal means the gene involved is located on one of the numbered chromosomes. Dominant means that a child only needs to inherit one copy of the mutated gene, from either biological parent, to be affected by the disease.
People affected by an autosomal dominant disease have a 50% chance of passing on the mutated gene to their biological child.