PITX2 and atrial fibrillation: Polymorphisms in the chromosome locus 4q25, which contains two single-nucleotide polymorphisms (SNPs) (rs2200733, shown to be most strongly associated with atrial fibrillation (AF), and rs10033464, near pituitary homeobox 2 (PITX2)), have been shown to influence the risk of AF recurrence after catheter ablation [93].