Dear Editor,A recent report on renal responses to sevoflurane and isoflurane in patients undergoing donor nephrectomy by Ong Sio et al.1 is very interesting. The authors concluded that “the overall nephrotoxicity profile of sevoflurane and isoflurane-treated donor nephrectomy patients is minimal.” In fact, this report is concordant with previous observation reported by Kim et al.2 A great concern is on the possible forgotten effect of underlying genetic factors. The effect of sevoflurane and isoflurane can be modified by several polymorphisms such as MDR1 gene polymorphism3, beta1-adrenergic receptor gene polymorphism4 and γ-aminobutyric acid (GABA)A receptor.5 Therefore, a study is necessary to verify any confounding effect of the possible hidden non-wild type genetic polymorphisms.