ADRB1 and familial dilated cardiomyopathy: When secondary causes such as hypertension, coronary artery disease, and valvular disease are excluded, DCM is often linked to genetic predisposition, viral myocarditis, and autoimmune mechanisms.[8–10] Among various autoantibodies, the anti-β1-adrenergic receptor (anti-β1-AR) antibody is the most extensively studied and best characterized.