Marott et al. (2013) based on a genetic study with patients with AF, reported that I103T-A244S and A244S mutations in the AT1R were directly associated with the predisposition to the development of this condition in men. Indeed, the I103T and A244S mutations (Figure 1A) are located respectively in the AT1R transmembranes helices 3 (TM3) and 6 (TM6), regions that have been described to bear critical residues that compose binding pockets for peptide and non-peptide ligands in different GPCRs (de Gasparo et al., 2000; Martin et al., 2004; Balakumar and Jagadeesh, 2014). The gene discussed is AGTR1; the disease is atrial fibrillation.