ABCC2 polymorphisms and haplotype are associated with drug resistance in Chinese epileptic patients.
OBJECTIVE
Some study found that ATP-binding cassette (ABC) efflux transporters play an important role in antiepileptic drug resistance, especially ABCB1 and ABCC2. The aims of this study were to evaluate the relationship between the genetic polymorphisms of ABCC2 and ABCB1 and the therapeutic efficacy of antiepileptic drugs (AEDs) in Chinese epileptic patients.


METHODS
ABCB1 rs1045642 (3435C>T) and ABCC2 rs717620 (-24C>T), rs3740066 (3972C>T), and rs2273697 (1249G>A) polymorphisms loci in 537 Chinese epilepsy patients (217 drug resistant patients and 320 drug responders) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).


RESULTS
ABCC2 rs717620 -24TT genotype was significantly associated with drug resistant epilepsy (odds ratio [OR]= 4.06 [1.79-9.20], P= 0.001). The OR values of ABCC2 rs717620 -24 CT+TT genotypes and ABCC2 rs3740066 (3972C>T) CT+TT genotypes were markedly higher in drug resistant patients (OR = 1.57 [1.08-2.29], P= 0.018; OR = 1.49 [1.02-2.18], P= 0.038, respectively) compared with responsive patients. ABCC2 rs2273697 (1249G>A) and ABCB1 rs1045642 (3435C>T) polymorphisms were not associated with drug resistant epilepsy. Linkage disequilibrium (LD) test showed that the ABCC2 rs717620 were in strong LD with rs2273697 (D'= 0.694) and rs3740066 (D'= 0.699). The frequencies of haplotypes TGT (ABCC2 -24C>T/ABCC2 1249G>A/ABCC2 3972C>T) in resistant patients was significantly higher than those in responsive patients (21.0% vs. 14.2%, P < 0.05).


CONCLUSIONS
ABCC2-24C>T, 3972C>T polymorphisms and one ABCC2 haplotype is associated with AED resistance; ABCC2 1249G>A and ABCB1 3435C>T polymorphisms are not associated with AED resistance in our study. These data suggest that ABCC2 polymorphisms and haplotype may affect the response of antiepileptic drugs.
Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University Xiangya School of Medicine, Changsha, China.
Jian
J
Qu
Bo-Ting
BT
Zhou
Ji-Ye
JY
Yin
Xiao-Jing
XJ
Xu
Ying-Chun
YC
Zhao
Guang-Hua
GH
Lei
Qiang
Q
Tang
Hong-Hao
HH
Zhou
Zhao-Qian
ZQ
Liu
D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use*; D044466:Asian People; D002681:China / Q000453:epidemiology; D004351:Drug Resistance; D004827:Epilepsy / Q000188:drug therapy* / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D055815:Young Adult
D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000927:Anticonvulsants; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C513055:ABCB1 protein, human; C000715087:ABCC2 protein, human