It has been proposed that genetic polymorphisms in renal transporters may predispose individuals to have high intracellular tenofovir concentrations, thus increasing the chance of developing tubular toxicity. ABCC2 polymorphisms have been evaluated, and the haplotype “CATC” [a combination of the polymorphisms at positions –24 (rs717620), 1249 (rs2273697), 3563 (rs8187694), and 3972 (rs3740066) within the ABCC1 gene] and the allele -24C > T (rs717620) have both been associated with an increased incidence of tenofovir-associated tubular toxicity