Hypertrophic obstructive cardiomyopathy (HOCM) most commonly results from mutations in which sarcomeric protein?
- A Beta-myosin heavy chain (MYH7) or myosin-binding protein C (MYBPC3) ✓
- B Dystrophin
- C Desmin
- D Lamin A/C (LMNA)
Explanation
Familial HCM is predominantly caused by autosomal dominant mutations in genes encoding sarcomeric proteins; the two most common are MYH7 (beta-myosin heavy chain, ~35-40%) and MYBPC3 (myosin-binding protein C, ~40-45%), together accounting for ~70-80% of cases. Mutations in troponin T, troponin I, and tropomyosin account for most remaining cases. Dystrophin mutations cause X-linked dilated cardiomyopathy (Duchenne/Becker). Desmin mutations cause desminopathy (restrictive/dilated cardiomyopathy with conduction disease). LMNA mutations cause laminopathy (dilated cardiomyopathy with arrhythmias and sudden cardiac death).
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
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