The original candidate genes thought to be involved in AF were β-adrenergic receptor (ADRB1)13 and α-adrenergic receptor (ADRA2)14 located on 10q23–q26, and G-protein-coupled receptor kinase (GPRK5) 15, which interacts with adrenergic receptors. This evidence concerns the gene ADRB1 and atrial fibrillation.