Alternative Names
Hypertrophic obstructive cardiomyopathy (HOCM); idiopathic hypertrophic subaortic stenosis (IHSS); asymmetric septal hypertrophy (ASH)
Symptoms & Characteristics
Hypertrophic cardiomyopathy (HCM) is a genetic disease characterized by abnormal thickening of the heart muscle. HCM is also known as hypertrophic obstructive cardiomyopathy (HOCM), idiopathic hypertrophic subaortic stenosis (IHSS) and asymmetric septal hypertrophy (ASH).
Symptoms of HCM include shortness of breath, chest pain, lightheadedness, fainting, fatigue, palpitations, and sudden cardiac death. HCM is the most common cause of sudden death in adolescents and young adults. Often, there are no other symptoms before sudden death occurs.
Treatment
Medications that decrease heart rate and blood pressure are used to treat the symptoms of HCM. Affected people with more severe symptoms may need surgery to remove some of the excess heart muscle. Alternatively, a procedure called alcohol septal ablation may be used to shrink the heart muscle without open heart surgery. Affected people at high risk for sudden death are sometimes treated with an implantable cardioverter-defibrillator (ICD). High risk individuals are also advised to avoid participation in competitive sports.
Early diagnosis is important so that a person's risk can be evaluated and proper treatment can be started.
If someone experiences any of the symptoms associated with HCM, it is important to see a doctor.
How Common Is It?
About 1 in 500 people are believed to be affected with HCM.
Genetics & Inheritance
HCM is primarily caused by mutations in genes that produce different components of the sarcomere - one of the basic units of striated muscle. This form of HCM is characterized by thickening of the cardiac muscle of the left ventricle (called left ventricular hypertrophy) that develops in the absence of identified, predisposing cardiac and/or cardiovascular conditions. Currently, mutations in at least 12 different genes have been associated with this form of HCM. More than 600 individual mutations have been identified in these 12 genes.
In this form of HCM, having a mutation in a single gene copy is sufficient to cause the disease. This is called autosomal dominant inheritance. An affected person has a 50% chance with each pregnancy to have an affected child.
- Other less common forms of HCM have been identified in some families. These forms are also caused by mutations in genes essential to proper heart muscle functioning.
Genetic testing may help identify the causative mutation, which may provide insight into symptom severity. Once the gene has been identified in one family member, other family members can be identified who are at risk for developing HCM.
Genetic Testing
Clinical genetic testing for some of genes associated with hypertrophic cardiomyopathy may be available through an in person genetic consultation for people who are considered at risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.
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