Hypertrophic cardiomyopathy (HCM) is most commonly caused by mutations in sarcomeric proteins. The most frequently mutated gene encodes:

• A Dystrophin — causing X-linked dilated cardiomyopathy
• B Lamin A/C — causing dilated cardiomyopathy with conduction disease
• C Beta-myosin heavy chain (MYH7) or myosin-binding protein C (MYBPC3) ✓
• D Titin (TTN) — the most common cause of familial dilated cardiomyopathy

Explanation

HCM is an autosomal dominant disorder caused by gain-of-function mutations in sarcomeric proteins. Beta-myosin heavy chain (MYH7) and cardiac myosin-binding protein C (MYBPC3) together account for approximately 50-75% of all HCM mutations. These mutations alter the contractile properties of the sarcomere, increasing its sensitivity to calcium and causing myocyte disarray and hypertrophy. Dystrophin mutations cause X-linked DCM. Lamin A/C and titin mutations cause dilated, not hypertrophic, cardiomyopathy.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.