Familial dilated cardiomyopathy (DCM) is associated with thinning of cardiac muscle, resulting in enlargement of the affected chamber(s). Reduced efficiency of cardiac blood flow causes progressive thinning which, untreated, may result in heart failure. Onset of symptoms typically occurs in adulthood, and these include arrhythmia, dyspnea, extreme fatigue, exercise intolerance, syncope, and swelling of the lower extremities. In some cases, sudden cardiac death in an undiagnosed or asymptomatic individual can occur.
Arrhythmogenic right ventricular cardiomyopathy (ARVC) occurs when right ventricular tissue breaks down and is replaced by fat and scar tissue. Heart palpitations, syncope, and swelling of the legs can occur. In addition, cardiac arrest may be triggered by exercise, so sudden death in young athletes has been reported with this condition. Disease presentation is highly variable, even within families.
Treatments include pharmocologic therapies, implanted defibrillators, and in severe cases, heart transplant. While some types demonstrate autosomal recessive or X-linked inheritance, most forms are inherited in an autosomal dominant pattern. This panel consists of 51 genes that are associated with these conditions.