CYP2R1 and rheumatoid arthritis: The distribution of genotypic and allelic frequencies was for rs10741657 CYP2R1, the most frequent genotype in both RA patients and CS was AG (47% in both groups), followed by GG (RA: 41% vs. CS: 43%) and AA (RA: 12% vs. CS: 10%) (Table 3).