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Disease Profile

Familial hypertrophic cardiomyopathy

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

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ICD-10

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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.

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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)

Cardiomyopathy familial hypertrophic; Heritable hypertrophic cardiomyopathy; Familial HCM

Categories

Heart Diseases

Summary

Familial hypertrophic cardiomyopathy (HCM) is an inherited heart condition characterized by thickening of the heart muscle. The thickening most often occurs in the muscle wall that separates the left and right ventricles from each other (interventricular septum). This may restrict the flow of oxygen-rich blood from the heart, or it may lead to less efficient pumping of blood. Signs and symptoms can vary. While some people have no symptoms, others may have chest pain, shortness of breath, palpitations, lightheadedness, dizziness, and/or fainting. Even in the absence of symptoms, familial HCM can have serious consequences such as life-threatening arrhythmias, heart failure, and an increased risk of sudden death. Familial HCM may be caused by mutations in any of several genes and is typically inherited in an autosomal dominant manner.[1] Treatment may depend on severity of symptoms and may include medications, surgical procedures, and/or an implantable cardioverter-defibrillator (ICD).[2]

Cause

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.[1]

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.[1]

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.[1]

Diagnosis

Familial hypertrophic cardiomyopathy (HCM) is caused by mutations in any of several known genes, and possibly other genes that have not yet been identified.[1] 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.[3]

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).[3]

Testing Resources

    Treatment

    FDA-Approved Treatments

    The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

    • Dehydrated alcohol(Brand name: Ablysinol) Manufactured by Belcher Pharmaceuticals, LLC
      FDA-approved indication: June 2018 approved to induce controlled cardiac septal infarction to improve exercise capacity in adults with symptomatic hypertrophic obstructive cardiomyopathy who are not candidates for surgical myectomy.

    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

      Organizations Providing General Support

        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

        • The American Heart Association has an information page on Familial hypertrophic cardiomyopathy. The American Heart Association is the nation’s oldest and largest voluntary organization dedicated to fighting heart disease and stroke.
        • The Mayo Clinic Web site provides further information on Familial hypertrophic cardiomyopathy.
        • Genetics Home Reference (GHR) contains information on Familial hypertrophic cardiomyopathy. This website is maintained by the National Library of Medicine.

          In-Depth Information

          • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
          • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
          • 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) lists the subtypes and associated genes for Familial hypertrophic cardiomyopathy in a table called Phenotypic Series. Each entry in OMIM includes 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.
          • PubMed is a searchable database of medical literature and lists journal articles that discuss Familial hypertrophic cardiomyopathy. Click on the link to view a sample search on this topic.

            Videos/Presentations

              References

              1. Familial hypertrophic cardiomyopathy. Genetics Home Reference. August, 2015; https://ghr.nlm.nih.gov/condition/familial-hypertrophic-cardiomyopathy.
              2. Hypertrophic cardiomyopathy. Mayo Clinic. October, 2016; https://www.mayoclinic.org/diseases-conditions/hypertrophic-cardiomyopathy/home/ovc-20122102.
              3. Allison L Cirino and Carolyn Ho. Hypertrophic Cardiomyopathy Overview. GeneReviews. January 16, 2014; https://www.ncbi.nlm.nih.gov/books/NBK1768/.

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