الملخص الإنجليزي
Recently, a G protein-coupled receptor 40 (GPR40) gene has been highlighted as a new gene that may be associated to T2DM. It was shown that the GPR40 receptor is expressed predominantly in the pancreatic B-cells and that it mediates an amplifying effect of free fatty acids on glucose-induced insulin secretion. For this, this study aimed to examine the coding and promoter regions of the GPR40 gene for variations by sequencing and to assess whether identified variants were associated with T2DM in Omanis. Genotyping of the GPR40 gene were performed for 89 T2DM samples and 40 control samples. One single nucleotide polymorphism (SNP) was found in the coding region (G/A) and two consecutive SNPs in the promoter region (T/C and G/A). For each SNP, allelic and genotypic frequencies were calculated. The results indicated that allele A of the G/A SNPs in the coding region as well as the promoter region was the common allele in both groups. For the T/C SNP in the promoter region, allelic frequencies of 0.57 and 0.43 were calculated for the T and C alleles respectively in T2DM group. The control group had a frequency of 0.6 for allele T and 0.4 for allele C. Genotype frequencies, for each SNP, were used to test for any associations with type 2 diabetes. None of the three SNPs found in this study was associated with T2DM in Omanis. Haplotype reconstruction and analysis were performed for the promoter SNPs. The results showed no significant difference in haplotype frequencies between the two tested groups. From these results we concluded that variations in the promoter and coding regions of the GPR40 gene found in Omani individuals do not appear to be associated with type 2 diabetes.
