THE RELATIONSHIP OF TWO XANTHINE OXIDASE SINGLE NUCLEOTIDE POLYMORPHISMS TO HYPERURICEMIA, GOUT, AND DOSE OF XANTHINE OXIDASE INHIBITOR

Background: There is evidence linking xanthine oxidase (XO) single nucleotide polymorphisms (SNPs) to multiple medical conditions. The relationship of XO SNPs to hyperuricemia/gout is limited. An in vitro study of serum from healthy adults found two XO SNPs at 2107A > G and 3662A > G associated with a two-fold higher activity of the enzyme. Materials and Methods: The main outcomes of this study were to determine if the presence of either 2107A > G or 3662A > G XO SNP led to the occurrence of hyperuricemia, gout, or necessitated a higher dose of XO inhibitor (XOI) to achieve a treatment goal of less than 6 mg/dL. A total of 72 patients were enrolled in the hyperuricemia/gout group; 41 in the control group. XO SNPs were amplified and sequenced. Patient interviews and chart reviews gathered demographic data, use of XOI, comorbidities, and serum uric acid levels. Results: The 2107A > G SNP was detected in six patients with hyperuricemia/gout and two patients in the control group. There was no association between either XO SNP with the occurrence of hyperuricemia/gout (p = 0.709). A higher dose of allopurinol was needed to achieve a treatment serum uric acid goal of less than 6 mg/dL (p = 0.049). The 3662A > G SNP was not identified in any patients in the either group of the study. Conclusion: While the presence of 2107A > G SNP had no relationship to hyperuricemia or gout in our cohort it did affect the dose of allopurinol needed to achieve a treatment goal of less than 6 mg/dL. The 3662A > G SNP was not identified in our sample.