The association of polymorphic sites in some genes with type 1 diabetes mellitus in a sample of Egyptian children

Abstract

Background: The major histocompatibility complex (MHC) genes have been implicated as the major genetic component in the predisposition to type 1 diabetes mellitus (T1DM). Other loci outside the MHC had also been reported to contribute in the susceptibility of T1DM. The aim of this study was to examine the role of some variants of polymorphic sites in some genes associated with T1DM in a sample of Egyptian children.
Patients and methods: 60 patients with T1DM from the diabetes clinic at Alexandria University Children’s Hospital, and 60 healthy individuals were enrolled in this study. Genomic DNA was extracted using isopropanol precipitation method. Interleukin 18 (IL-18), interleukin 10 (IL-10), vitamin D receptor (VDR), protein tyrosine phosphatase non-receptor type 22 (PTPN22) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) were genotyped.
Results: The findings obtained from logistic regression analysis suggest that the IL-18 single nucleotide polymorphisms SNP-137 G>C (rs#187238), the VDR Fok1 SNP T>A (rs#2228570) and the SNP-1123 C>G (rs#2488457) in PTPN22 gene showed a significant difference between patients and controls (P = 0.026, 0.030, and 0.003, respectively). The genotype distributions of PTPN22 SNP-1858, CTLA-4 SNP 49, IL-10 SNP-819, IL-18 SNP-607, and VDR BsmI SNP G>A did not show any significant difference.
Conclusion: The IL-18 SNP-137 G>C (rs#187238), VDR SNP-Fok1 T>A (rs#2228570), and the SNP-1123 C>G (rs#2488457) in PTPN22 gene may have an effect on the occurrence of T1DM in Egyptian children. Further large-scale, population-based, case-control studies are needed.

Keywords: Genes; Genomic DNA; Single nucleotide polymorphism; Type 1 diabetes mellitus