DCM is marked by ventricular dilation with impairedsystolic function (left ventricular ejection fraction, LVEF <40%), andtruncating mutations in the TTN gene are observed in 30–40% of cases.In later stages, DCM frequently leads to malignant ventricular arrhythmias [41].RCM is primarily characterized by increased ventricular stiffness that results indiastolic dysfunction [42]. The gene discussed is TTN; the disease is familial dilated cardiomyopathy.