Association between two functional SNPs of SCN1A gene and efficacy of carbamazepine monotherapy for focal seizures in Chinese Han epileptic patients.

OBJECTIVE: To investigate whether single nucleotide polymorphisms (SNPs) of rs2298771 and rs3812718 of the sodium channel α-subunit type 1 (SCN1A) gene affect the efficacy of carbamazepine (CBZ) treatment for seizures in Chinese Han epileptic patients. METHODS: SNP rs2298771 and rs3812718 of the SCN1A gene from 628 patients were genotyped. CBZ monotherapy was administered to the subjects with new-onset partial seizures. The efficacy was defined as the decrease in the number of seizures. Four semi-quantitative levels were used to assess the efficacy: seizure-free (SF), >75% seizure decrease (SD), 50%-75% SD, and <50% SD in the number of seizures compared with patients' initial conditions. RESULTS: After the 12 month treatment with CBZ monotherapy, the rate of SF patients with G allele of the SNP rs2298771 was significantly lower than that in patients with the AA genotype (P=0.003). The heterozygote and homozygote of the G allele at SNP rs2298771 predicted the low SF rate (OR=2.101, 95% CI 1.289-3.425). Marginal significance was observed between the dichotomous efficacy of SF and non-SF in 3 partial seizure types (P=0.028). CONCLUSION: rs2298771 is significantly associated with the efficacy of CBZ monotherapy in Chinese Han epileptic patients.