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Disease Profile

Schwannomatosis

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

Adult

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ICD-10

Q85.0

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

Neurilemmomatosis congenital cutaneous; Congenital cutaneous neurilemmomatosis; Neurofibromatosis type 3;

Categories

Congenital and Genetic Diseases; Nervous System Diseases; Rare Cancers;

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 (mutations) 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. Treatment is based on the signs and symptoms present in each person but may include medications and/or surgery.[1][2]

Symptoms

Signs and symptoms of the schwannomatosis often develop during adulthood between ages 25 and 30. Affected people generally have multiple schwannomas, which are benign tumors of the nervous system. In schwannomatosis, these tumors can grow along any nerve in the body, although they are less common on the vestibular nerve (vestibular schwannomas, also known as acoustic neuromas). People with vestibular schwannomas, especially those with tumors affecting the vestibular nerve on both sides of the head (bilateral), may have neurofibromatosis type 2 instead.[1][2]

The signs and symptoms associated with schwannomatosis vary based on the size and location of the schwannomas. The most common symptom is chronic pain, which can develop as a growing schwannoma presses on nerves or surrounding tissues. Some people may develop a mass if the schwannomas is located just beneath the skin. Others can experience neurological symptoms such as numbness; tingling; and/or weakness in the fingers and toes.[1][2]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Abnormality of the skin
0000951
Abnormality of the vertebral column
Abnormal spine
Abnormal vertebral column
Abnormality of the spine

[ more ]

0000925
Autosomal dominant inheritance
0000006
Incomplete penetrance
0003829
Meningioma
0002858
Schwannoma
0100008
Somatic mutation
0001428
Spinal cord tumor
Tumor of the spinal cord
0010302
Variable expressivity
0003828

Cause

Some cases of schwannomatosis are caused by changes (mutations) in the SMARCB1 or LZTR1 genes.[2] SMARCB1 and LZTR1 are tumor suppressor genes, which means that they encode a protein that stops cells from growing and dividing too rapidly or in an uncontrolled way. Mutations in these genes result in abnormal proteins that are unable to carry out their normal roles. This contributes to the development of the many different types of tumors found in schwannomatosis.

When schwannomatosis is caused by a mutation in SMARCB1 or LZTR1, the affected person is typically born with one mutated copy of the gene in each cell and is, therefore, genetically predisposed to develop the tumors associated with the condition. For a tumor to form, two copies of the gene must be altered. The mutation in the second copy of the gene is considered a somatic mutation because it occurs during a person's lifetime and is not inherited.

In affected people without a mutation in SMARCB1 or LZTR1, the underlying cause of the condition is unknown.

Diagnosis

A diagnosis of schwannomatosis is often suspected based on the presence of characteristic signs and symptoms, especially if there are other family members with the condition. Additional testing can then be ordered to further support the diagnosis and rule out other conditions with similar features (namely, neurofibromatosis type 2). This may include:[2]

  • Tumor pathology confirming that the growths are, in fact, schwannomas
  • Imaging studies, such as an MRI examining the vestibular nerve. It is important to rule out the presence of bilateral (affecting both sides) vestibular schwannomas which would be suggestive of neurofibromatosis type 2 rather than schwannomatosis
  • Genetic testing for a change (mutation) in the SMARCB1 or LZTR1 genes. Unfortunately, genetic testing is not informative in all people affected by schwannomatosis.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

    Treatment

    Treatment for schwannomatosis is based on the signs and symptoms present in each person. For example, pain is one of the most common symptoms of the condition. Treatment with medications such as gabapentin or pregabalin and the use of short-acting opioids and/or nonsteroidal anti-inflammatories for pain can be successful for many patients. If pain cannot be managed with other means or if the schwannomas are causing other symptoms, they can be surgically removed. However this treatment is often used as a last resort because surgery may put patients at risk of further neurologic problems.[2]

    Organizations

    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      Where to Start

      • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
      • Genetics Home Reference (GHR) contains information on Schwannomatosis. This website is maintained by the National Library of Medicine.
      • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
      • The Children's Tumor Foundation provides information about schwannomatosis. Click on the above link to access this information.

        In-Depth Information

        • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Schwannomatosis. Click on the link to view a sample search on this topic.

          References

          1. Neurofibromatosis Fact Sheet. National Institute of Neurological Disorders and Stroke. February 2015; https://www.ninds.nih.gov/disorders/neurofibromatosis/detail_neurofibromatosis.htm#279853162.
          2. Kaleb Yohay, MD; Amanda Bergner, MS, CGC. Schwannomatosis. UpToDate. January 2015; Accessed 7/26/2015.
          3. Evans DG. Neurofibromatosis 2. GeneReviews. Updated March 15, 2018; https://www.ncbi.nlm.nih.gov/books/NBK1201/.

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