In the DCM subgroup analysis, we found that the percentage of B1 cells in patients with DCM who were β1-AR autoantibody-positive was significantly lower than that in β1-AR autoantibody-negative patients (1.84 ± 0.78% vs. 3.05 ± 1.56%, P = 0.02) (Fig. 2B). The gene discussed is ADRB1; the disease is familial dilated cardiomyopathy.