SCN1A polymorphisms influence the antiepileptic drugs responsiveness in Jordanian epileptic patients

BACKGROUND: The aim of this study was to evaluate whether the voltage-gated sodium channel alpha subunit 1 (SCN1A) gene polymorphisms influence the responsiveness of Jordanian epileptic patients to antiepileptic drugs (AEDs). METHODS: A total of 72 AEDs-treated epileptics were polymerase chain reaction (PCR)-genotyped for six single nucleotide polymorphisms (SNPs), including SCN1A rs2298771, rs3812718, rs3812719, rs2217199, rs2195144 and rs1972445. Genotype and allele distributions in drug-responsive and drug-resistant patients were compared. The six SNPs haplotypes were examined, and the linkage disequilibrium (LD) was assessed. RESULTS: The genotypes of drug-resistant and drug-responsive groups were in Hardy-Weinberg equilibrium. Three genetic polymorphisms of the SCN1A gene seemed to influence the resistance to AEDs, on the level of alleles and genotypes. Data revealed that rs2298771 G allele, rs3812719 C allele, and rs2195144 T allele increased the risk of developing AEDs-resistance (OR=2.9; 95%CI= 1.4-5.9, p=0.003; OR=2.4; 95%CI=1.2-4.7, p=0.01; OR=2.3; 95%CI=1.2-4.7, p=0.01), respectively. Haplo type analysis of SCN1A polymorphisms revealed high-degree LD associated with resistance to AEDs. A synergetic effect appears with highly significant association in GCCATG haplotype of rs2298771, rs3812718, rs3812719, rs2217199, rs2195144, and rs1972445 respectively (OR=2.8; 95%CI=1.5-6.2, p=0.002). CONCLUSIONS: Data suggests that SCN1A polymorphisms could influence the resistance to AEDs in Jordanian epileptics at three SNPs (rs2298771; rs3812719; rs2195144). Additionally, haplotype analysis indicated a substantial degree of LD between the six SCN1A polymorphisms. Further investigation with larger sample size is needed to confirm the results of the current study.