ABCG2 and chronic kidney disease: In this study, to clarify the physiological role of intestinal urate excretion via ABCG2 in humans, we performed genotyping of ABCG2 dysfunctional variants in end-stage renal disease (hemodialysis) patients whose serum uric acid (SUA) levels are extremely elevated9, 10 and urate excretion almost depends on intestinal excretion via ABCG2 because of their almost complete absence of renal urate excretion.