Table 1. Genes associated with sarcomere hypertrophic cardiomyopathy.
| Gene | Protein | Estimated prevalence in HCM (%) | Notes* | |
|---|---|---|---|---|
| Sarcomere | Force generation/Transmission | |||
| Thick myofilament | ||||
| MYH7 | β-Myosin heavy chain | 25–40% | - Prognosis variable depending on site of genetic variant; homogeneity within families | |
| - Sometimes restrictive cardiomyopathy phenotype | ||||
| MYBPC3 | Myosin-binding protein C | 25–40% | - Prognosis variable depending on site of genetic variant; homogeneity within families | |
| MYL2 | Myosin light chain 2, regulatory | <5% | ||
| MYL3 | Myosin light chain 3, essential | <5% | ||
| Thin myofilament | ||||
| TNNT2 | Cardiac troponin T | 5–10% | - Left ventricular hypertrophy is rare in children with TNNT2 mutations. Particularly among males, SCD-predisposition and minimal hypertrophy (some reports) | |
| TNNI3 | Cardiac troponin I | 5% | - This mutation is associated with sudden death at any age and dilated cardiomyopathy-like features in those aged >40 years | |
| - Sometimes restrictive cardiomyopathy phenotype | ||||
| TNNC1 | Cardiac troponin C | <1% | ||
| ACTC1 | Cardiac α-actine | <1% | - Benign prognosis and apical LV hypertrophy morphology | |
| TPM1 | α-Tropomyosin | 1–5% | ||
HCM = hypertrophic cardiomyopathy; LV = left ventricular; SCD = sudden cardiac death.
*As the field of prognostically relevant mutations expanded, a series of studies directly contradicted, or at least failed to replicate, many of these initial observations.