ALLELE AND GENOTYPE DISTRIBUTION OF VOLTAGE-GATED SODIUM CHANNEL GENE POLYMORPHISMS IN SOUTH INDIAN DESCENT

Background: Genetic polymorphisms in voltage-gated sodium channel (VGSCNA) genes play a significant role in the development of neurological diseases. Various studies have found that there is a significant variation in the genetic makeup of Indians, with other genetic groups having been identified such being Dravidian South Indian population. Hence, we aimed to establish the normative frequency of five SNPs of four VG-SCNA gene subunits in South Indians and wanted to assess the similarity or dissimilarity with other distinct genetic groups. Materials and Methods: In this study, we used TaqMan single nucleotide polymorphism (SNP) genotyping assays to evaluate the genotypes of five VG-SCNA genetic polymorphisms associated with neuronal toxicity in 167 healthy unrelated South Indian volunteers on real time thermocycler (ABI Prism 7300, foster city, CA, USA). Result: Among 167 healthy volunteers, there were 89 males and 78 females with a mean (SD) age of 25.5 (±5.5) years. The minor allele frequencies of the studied genetic polymorphisms rs2302237 (SCN4A), rs11720524 (SCN5A), rs6746030, rs6754031 (SCN9A), and rs12632942 (SCN10A) were 18.6%, 21.6%, 16.8% 28.8%, and 22.2% respectively. The frequencies of the studied genetic polymorphisms show statistically significant differences from other ethnic groups in five out of the five genetic polymorphisms studied. Conclusion: Considerable dissimilarities in frequencies of genetic polymorphisms were found between the South Indian population and other major ethnic populations worldwide with respect to SCN4A (rs2302237), SCN5A (rs11720524), SCN9A (rs6746030, rs6754031), and SCN10A (rs12632942).