title: SCN1AIVS5-91G>A polymorphism is associated with susceptibility to epilepsy but not with drug responsiveness.
abstract: Sodium channel alpha subunit type 1 (SCN1A) is voltage gated ion channel which plays critical role in membrane excitability. A common SCN1A IVS5-91G>A (rs3812718) allele has been attributed to be a possible modifying factor for epilepsy susceptibility and therapeutic response. In the present study, we enrolled 485 epilepsy patients and 298 age-sex matched controls free of neurological deficits. Therapeutic response of carbamazepine/oxcarbamazepine (CBZ/OXC) and other antiepileptic drugs were observed in terms of drug responsiveness and drug resistance. Genotyping of SCN1A IVS5-91G>A is done by Taqman custom designed assay; in a real time7500HT System. We observe highly significant association [(P-values for GA (P = 6.58 × 10(-5), OR = 2.13, 95% CI = 1.47-3.09) and AA (P = 4.11 × 10(-9), OR = 3.59, 95% CI = 2.35-5.50)] at variant genotypes as well as A allele (P = 6.92 × 10(-11)), OR = 1.99, 95%, CI = 1.62-2.45) in epilepsy patients versus control subjects. The relative risk for epilepsy susceptibility due to variant containing genotypes (GA + AA) was also significant (P = 1.64 × 10(-5); OR = 2.56; 95% CI = 1.80-3.65) when compared with homozygous wild-type GG. The risk in recessive model (P = 1.34 × 10(-5); OR = 2.12; 95% CI = 1.51-2.97) was also apparent when compared with GA + GG. In case-only analysis, we evaluated the effect of SCN1A IVS5-91G>A polymorphism with drug resistance of anti-epileptic drug therapies. However, we did not observe significant associations either with patients showing drug resistance to CBZ/OXC monotherapy or polytherapy. In conclusion, we report that SCN1AIVS5-91G>A polymorphism is associated with epilepsy susceptibility but not with drug responsiveness in epilepsy patients from North India.
authors: Department of Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareli Road, Lucknow 226014, India.
authors: Ritu
authors: R
authors: Kumari
authors: Ram
authors: R
authors: Lakhan
authors: Surendra
authors: S
authors: Kumar
authors: R K
authors: RK
authors: Garg
authors: U K
authors: UK
authors: Misra
authors: J
authors: J
authors: Kalita
authors: Balraj
authors: B
authors: Mittal
mesh_terms: D000927:Anticonvulsants / Q000627:therapeutic use*; D004351:Drug Resistance / Q000235:genetics*; D004827:Epilepsy / Q000188:drug therapy* / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D007194:India; D008297:Male; D062550:NAV1.1 Voltage-Gated Sodium Channel / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D000927:Anticonvulsants; D062550:NAV1.1 Voltage-Gated Sodium Channel; C568242:SCN1A protein, human