Whole exon screening of SLC2A4 gene and the association of rs5435 with type 2 diabetes in a Bangladeshi case-control study

Type 2 diabetes (T2D) is a multifaceted disease influenced by both genetic and environmental factors, posing significant global health challenges. Polymorphisms in the SLC2A4 gene encoding the glucose transporter 4 (GLUT4), have been linked to insulin resistance and T2D. This study, therefore, aims to identify and analyze genetic variants within the SLC2A4 gene and determine their association with T2D risk through a Bangladeshi case-control study. A total of 239 individuals were enrolled in the study, including 127 T2D patients and 112 controls. All 11 exons of the SLC2A4 gene were sequenced in 20 individuals. Exons 2, 3, 4, and 5 of GLUT4 were then sequenced in an additional 99 participants. For the remaining 120 participants, a TaqMan probe-based RT-PCR was conducted to genotype rs5435. Four genetic variants were initially identified, including one synonymous variant (rs5435) in exon 4. There was no significant difference in the allele frequency of the wild-type allele T and variant allele C between the two groups (OR: 1.31, p = 0.13). Genotypic distribution revealed that individuals who were either heterozygous or homozygous for the variant allele are at an increased risk for developing T2D compared to those who are homozygous for the non-risk allele (p = 0.042), suggesting that the SNP could be considered to have a dominant effect on the likelihood of developing T2D. Additionally, in silico analysis revealed that the rs5435 variant introduces an additional loop in the mRNA secondary structure, which is energetically less stable and therefore may interfere with the protein’s biological function and play a role in the pathogenesis of T2D. However, further studies with larger cohorts are necessary to validate the impact of rs5435 on the risk of T2D in our population.