The Large-scale Deletions and Copy Numbers of Mitochondrial DNA in Gout Patients Treated with Allopurinol

Allopurinol is now the first-line treatment for managing gout and its increasing usage has brought more gout patients at risk of developing allopurinol-induced hypersensitive reactions. Up to now, our attempts to identify the biomarkers for hypersensitivity to allopurinol are still finite. Besides, the association between drug-induced hypersensitive reactions and some mitochondrial DNA (mtDNA) alterations has been proved but remains unclear in gout patients. In this study, 41 blood samples of gout patients prescribed with allopurinol including 22 hypersensitive and 29 tolerant ones were used to analyze their mtDNA large-scale deletions through PCR and determine the mtDNA deletion level and the copy number by quantitative PCR. The results indicated that the mtDNA large-scale deletions and mtDNA copy number of the hypersensitive group were lower than that of the tolerant one (p < 0.05). However, no association was found between the mtDNA deletion level and the appearance of hypersensitive reactions in gout patients. In addition, the study showed that the mtDNA deletion level and copy number were negatively correlated with the copy numbers of mitochondrial DNA in gout patients (R = -0.3495; p = 0.0119) and allopurinol hypersensitive group (R = -0.6744; p = 0.0005). Thus, a decrease in mtDNA copy number might serve as a potential biomarker for further investigation to assess the risk of hypersensitive reactions to allopurinol in gout patients. 
 