Clinical Information

Cardiomyopathies are a group of disorders characterized by disease of the heart muscle. Cardiomyopathy can be caused by either inherited, genetic factors or nongenetic (acquired) causes, such as infection or trauma.(1) When the presence or severity of the cardiomyopathy observed in a patient cannot be explained by acquired causes, genetic testing for the inherited forms of cardiomyopathy may be considered.

The hereditary form of hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy in the absence of other cardiac or systemic causes that may cause hypertrophy of the heart muscle, such as longstanding, uncontrolled hypertension or aortic stenosis. The incidence of HCM in the general population is approximately 1:200 to1:500, and it is estimated that 30% to 60% of cases can be attributed to a genetic etiology.(1) Hereditary forms of HCM are most often caused by genes encoding proteins of the cardiac sarcomere, the functional contractile unit of the heart muscle.

The clinical presentation of HCM can be variable, even within the same family. HCM can be apparently asymptomatic in some individuals but can cause sudden, life-threatening arrhythmias, increasing the risk of sudden cardiac death. Additionally, HCM may also be a feature of an underlying systemic condition such as Noonan syndrome, a mitochondrial disorder, or a metabolic storage disorder.(2)

Hereditary forms of HCM can follow autosomal dominant, autosomal recessive, and X-linked patterns of inheritance. Mitochondrial inheritance is also possible, however, genes associated with mitochondrial inheritance of HCM are not assessed on this panel.