Our result was similar to that of a recently published study investigating the association of another G-protein-coupled receptor autoantibody (against the M2-muscarinic acetylcholine receptor) with atrial fibrosis in AF patients; a positive correlation was found between serum autoantibody levels and collagen volume in LA appendages (Ma et al., 2019). The gene discussed is CHRM2; the disease is atrial fibrillation.