Familial hypertrophic cardiomyopathy

What causes familial hypertrophic cardiomyopathy?

Familial hypertrophic cardiomyopathy (HCM) is caused by mutations in any of several genes. The genes most commonly responsible are the MYH7 , MYBPC3 , TNNT2 , and TNNI3 genes. Other genes that have not yet been identified may also be responsible for familial HCM.

The genes known to be responsible for familial HCM give the body instructions to make proteins that play important roles in contraction of the heart muscle. The proteins form structures in muscle cells called sarcomeres, which are needed for muscle contractions. Sarcomeres are made of protein fibers that attach to each other and release, allowing muscles to contract. The contractions of heart muscle are needed to pump blood to the rest of the body.

While it is unclear exactly how mutations in these genes cause familial HCM, they are thought to lead to abnormal structure or function of sarcomeres, or reduce the amount of proteins made. When the function of sarcomeres is impaired, normal heart muscle contractions are disrupted.

Last updated on 05-01-20

Is genetic testing available for familial hypertrophic cardiomyopathy?

Familial hypertrophic cardiomyopathy (HCM) is caused by mutations in any of several known genes, and possibly other genes that have not yet been identified. Genetic testing for HCM is most informative as a "family test" rather than a test of one person. Results are most accurately interpreted after merging both genetic and medical test results from multiple family members. Ideally, the family member first having genetic testing should have a definitive diagnosis of HCM and be the most severely affected person in the family. Genetic testing of at-risk, asymptomatic relatives is possible when the responsible mutation has been identified in an affected family member. Testing should be performed in the context of formal genetic counseling.

An algorithm showing a general approach to finding the specific genetic cause in people with HCM can be viewed here.

The Genetic Testing Registry (GTR) provides information about the genetic tests for familial HCM. 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.

As is often the case with genetic testing in general, there are benefits and limitations of genetic testing for familial HCM. Testing may confirm the diagnosis in a person with symptoms, and may help to identify family members at risk. However, results are sometimes unclear; testing cannot detect all mutations; and results cannot be used to predict whether a person will develop symptoms, age of onset, or long-term outlook (prognosis).

Last updated on 05-01-20

How is familial hypertrophic cardiomyopathy inherited?

Familial hypertrophic cardiomyopathy (HCM) is inherited in an autosomal dominant manner. This means that having only one changed (mutated) copy of the responsible gene in each cell is enough to cause features of the condition. When a person with an autosomal dominant condition has children, each child has a 50% (1 in 2) chance to inherit the mutated copy of the gene.

In rare cases, a person with familial HCM has a mutation in both copies of the responsible gene, which leads to more severe signs and symptoms.

Last updated on 05-01-20

Name: American Heart Association 7272 Greenville Avenue
Dallas, TX, 75231-4596, United States
Phone: 214-570-5978 Toll Free: 800-242-8721 Email: https://www.heart.org/en/forms/general-questions-and-latest-research-information Url: https://www.heart.org
Name: Hypertrophic Cardiomyopathy Association HCMA 18 East Main St. Suite 202
Denville, NJ, 07834, United States
Phone: 973-983-7429 Fax : 973-983-7870 Email: Support@4hcm.org Url: http://www.4hcm.org
Name: The Children's Heart Foundation PO Box 244
Lincolnshire, IL, 60069-0244, United States
Phone: 847-634-6474 Toll Free: 888-248-8140 Email: info@childrensheartfoundation.org Url: http://www.childrensheartfoundation.org/
Name: Heart Rhythm Society 1400 K Street, NW Suite 500
Washington, DC, DC, 20005, United States
Phone: 202-464-3400 Fax : 202-464-3401 Email: info@HRSonline.org Url: http://www.hrsonline.org/
Name: Heart Failure Society of America HFSA 6707 Democracy Blvd. Suite 925
Bethesda, MD, 20817, United States
Phone: 301-312-8635 Toll Free: 888-213-4417 Email: info@hfsa.org Url: http://www.hfsa.org/

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The RareGuru disease database is regularly updated using data generously provided by GARD, the United States Genetic and Rare Disease Information Center.

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