Association Analysis Of Drug-related Genetic Factors With Individual Differences In Response And Adverse Drug Reactions To Antiseizure Drugs In Children With Epilepsy

Epilepsy is a common neurologic disorder in children,with a global prevalence of 0.9%.Antiseizure drugs(AEDs)are the primary therapy for childhood epilepsy.However,about 30%children treated with AEDs have a poor response,and children with epilepsy have a higher incidence of adverse drug reactions(ADRs)compared with adults,with significant individual differences in response and safety related to AEDs.Genetic polymorphism is the root cause of significant individual differences in response and ADRs related to AEDs.It is reported that single-nucleotide polymorphism(SNP)of ABCB1,ABCC2,and SCN1A,SCN2A may cause the individual differences in response and safety associated with AEDs.However,there is no consensus on the relationship between ABCB1,ABCC2,SCN1A,SCN2A polymorphism,and AEDs response.Furthermore,the role of these SNPs in the response and ADRs to AEDs remains unclear,which is necessary to be explored.Objectives:Our study was designed to explore the association of candidate SNPs related to ABCB1,ABCC2,SCN1A,and SCN2A with the drug response and ADRs related to AEDs in children with epilepsy.Network pharmacology analysis was used to explore the potential mechanism of AEDs-induced ADRs.It is helpful to design the individualized AEDs therapy for children with epilepsy.Methods:A retrospective study including 233 Chinese with epilepsy treated by AEDs was carried out.The types of AEDs,the usage of AEDs,sex,history of febrile seizure,therapeutic response,and ADRs were collected.Blood samples of enrolled patients were collected to determine the plasma concentration of VPA using the enzyme multiplied immunoassay technique.The polymorphism of ABCB1 rs3789243,rs1128503,ABCC2 rs2273697,SCN1A rs1962842,rs6732655,rs6730344,rs10167228,rs3812718,rs2298771,SCN2A rs2304016,rs17183814 in enrolled patients were genotyped using Sequenom MassArray system.The children were divided into seizure-free groups and seizure groups according to their therapeutic response to AEDs,their age,sex,history of febrile seizure,and the type of AEDs were further analyzed.In addition,enrolled children were divided into ADRs groups and related non-ADRs according to the occurrence of ADR.Student’s t-test,the X2 test,and ANOVA were performed to analyze the association between response,ADRs,blood concentration,and candidate SNP,to gain the potential targets.A network pharmacological analysis involved protein-protein interaction and enrichment analysis was further constructed to perform a gene network of target genes-drugs-ADRs,exploring the potential mechanism of target genes in AEDs-induced ADRs.Results:A total of 233 children with epilepsy were included in this study,among the 233 patients,11 patients were unclassified.In response to AEDs,146(65.8%)patients were defined as seizure-free together with 76(34.2%)patients were defined as a seizure.There is no significant difference in VPA blood concentration in epileptic children with or without seizure-free.The frequency of ADRs in this study was 63.9%,and the main ADRs were digestive ADRs(dADRs)(35.6%),neurogenic ADRs(nADRs)(27.9%),weight gain(27.9%),and rash(14.6%).The association analysis between SNP and response to AEDs in children with epilepsy found that SCN2A rs17183814 polymorphism has a strong relationship with response to AEDs.The requency of AG genotype was higher in seizure-free group than that in seizure group(30.8%and 15.8%,respectively,P=0.012).The results of a stratified study showed that AG genotype was significantly higher in epileptic children with the age of initial diagnosis in 7～16 years old,the male children,epileptic children with a history of febrile seizure,and epileptic children with a good response to VPA monotherapy than those other children.The association analysis between SNP and ADRs to AEDs in children with epilepsy in found that ABCB1 rs3789243、rs1128503,ABCC2 rs2273697,SCN1A rs10167228、rs2298771 were associated with ADRs related to AEDs.1)In dADRs,frequency of ABCC2 rs2273697 GG genotype was higher in dADRs induced by VPA and OXC than that in non-dADRs(VPA:92.5%vs.77.6%,P=0.019;OXC:95.0%3.5%,P=0.027).The frequency of ABCB1 rs3789243 GG genotype in children with dADRs receving VPA was significantly lower than that in children without VPA-induced dADRs(26.4%48.6%,P=0.01).The frequency of SCN1A rs2298771 CT genotype in children with dADRs receving OXC was lower than that in children without OXC-induced dADRs(5.0%25.4%,P=0.029).2)In weight gain,frequencies of ABCB1 rs1128503 GA genotype,SCN1A rs10167228 TA genotype,and SCN1A rs2298771 CT genotype were higher in VPA-induced weight gain than that in non-weight gain(ABCB1 rs1128503:GA:61.4%42.4%,P=0.04;SCN1A rs10167228:TA:25.0%10.6%,P=0.036;SCN1A rs2298771:CT:27.3%10.6%,P=0.018).The frequency of ABCB1 rs3789243 GG genotype in children with weight gain receving OXC was lower than that in children without OXC-induced weight gain(20.0%46.5%,P=0.03).3)In nADRs,frequency of SCN2A rs17183814 AG genotype was lower in VPA-induced nADRs than that in non-nADRs(9.5%32.2%,P=0.003).Furthermore,network pharmacology was used to analyze the mechanism of target genes in ADRs related AEDs.A total of 924 genes related to VPA,132 genes related to OXC,14784 genes related dADRs and weight gain,and 20 genes related to ABCB1,20 genes related to ABCC2,and 20 genes related to SCN1A were collected by the protein-protein network and GO/KEGG analysis.Ten target genes defined as "ABCB1-VPA-ADRs" were investigated using gene network constrution,which was mainly involved in Drug metabolism-cytochrome P450,Linoleic acid metabolism,and Serotonergic synapse pathway/biological process.Additionally,four target genes were defined as ABCC2-OXC-ADRs,which were mainly involved in Steroid hormone biosynthesis,Retinol metabolism,and Drug metabolism-cytochrome P450,and Bile secretion pathway and biological process.No potential enrichment pathway was found after GO/KEGG analysis in five target genes defined as SCN1A-OXC-ADRs.Conclusions:Our findings showed that ABCB1,ABCC2,SCN1A,and SCN2A polymorphism may be the potential factors for individual differences in response and ADRs to AEDs.The selection of appropriate AEDs for children with different genotypes may help to achieve individualized and targeted therapy.Carriers with SCN2A rs17183814 AG genotype had a better response and safety to AEDs.Carriers with ABCB1 rs3789243 GG genotype had a lower risk to present VPA-induced dADRs and OXC-induced weight gain.Carriers with ABCB1 rs 1128503 GA genotype,SCN1A rs10167228 TA genotype,and SCN1A rs2298771 CT genotype were inclined to VPA-induced weight gain.Carriers with ABCC2 rs2273697 GG genotype tended to show dADRs caused by VPA and OXC.The potential involvement of ABCB1,ABCC2,and SCN1A in VPA or OXC-induced ADRs may be related to Drug metabolism regulated by cytochrome P450,linoleic acid metabolism,serotonergic synapse,steroid hormone biosynthesis,retinol metabolism,and bile secretion pathway.