Influence of UGT2B7 and UGT1A6 polymorphisms on plasma concentration to dose ratio of valproic acid in Chinese epileptic children

We explored the potential effects of genetic variations on the concentration to dose ratio (CDR) of valproic acid (VPA) in paediatric epilepsy patients. Two hundred and twenty-nine epileptic children on VPA monotherapy were included, and the VPA trough concentrations at steady-state of all subjects were determined. Nineteen single nucleotide polymorphisms (SNPs) of seven selected genes related to the metabolising enzymes and transporters of VPA were identified, and their influences on CDRVPA (a logarithmic transformation was performed if abnormally distributed) were evaluated. UGT2B7 rs7668258 (C>T) TT genotype was associated with a decrease in lnCDR(VPA) among epileptic children receiving VPA monotherapy (beta=-0.191, p = 0.036). Significantly lower lnCDR(VPA) was also observed in paediatric patients with UGT1A6 rs2070959 (A>G) GG genotype compared to those AA genotype (beta=-0.270, p = 0.021). This research indicated that UGT2B7 rs7668258 (C>T) and UGT1A6 rs2070959 (A>G) polymorphisms may be correlated to the normalised plasma concentrations of VPA in Chinese epileptic children. The associations could be abolished after Bonferroni's correction and our findings need to be validated in further and larger investigations.