Résumé
Several polymorphisms have been identified in the amino acid sequence of human insulin receptor substrate-1 [IRS-1]. The most prevalent one is glycine change to arginine at the codon 972 that was hypothesized to play a role in pancreatic beta-cell stimulus-coupled-insulin secretion and survival. The frequency of this variant among type I diabetic patients, their available normal sibs, and control subjects recruited from EI-Shatby Pediatric Hospital, Alexandria University were studied. The results showed that the frequency of Arg[972] IRS-1 variant was 14% in diabetic patients, 9.1% in normal sibs, and 4% in normal control subjects. Data revealed that Odds ratio showed that carriers of Arg[972] IRS-1 variant had four times increased risk for developing the disease. In sibs, the risk is increased by three fold in carriers of this variant as compared to sibs with the wild allele. In spite being non-significant, the results of the present work suggest that Arg[972] IRS-1 variant could be considered as a potential risk factor for developing type I diabetes although it was statistically non-significant, which may be attributed to the small sample size or methods of selection of cases