Recent studies have shown that sarcomeric mutations in troponin I (TNNI3), myosin‐binding protein (MYBPC3), β‐myosin heavy chain (MYH7), myosin light chain genes (MYL3), troponin T (TNNT2),α‐cardiac actin, troponin C (TNNC1), tropomyosin 1 and myosin light chain (MYL3 and MYL2), and nonsarcomeric mutations in filamin‐C and desmin (DES) are contributed to the pathogenesis of RCM.21, 22, 23, 24, 25, 26. The gene discussed is MYL3; the disease is cardiomyopathy, familial restrictive, 1.