The Potential Role of PTPN-22 C1858T Gene Polymorphism in the Pathogenesis of Type 1 Diabetes in Saudi Population

Single-nucleotide polymorphisms as important risk factors of diabetes among Middle East population

Diabetes is a chronic metabolic disorder that leads to the dysfunction of various tissues and organs, including eyes, kidneys, and cardiovascular system. According to the World Health Organization, diabetes prevalence is 8.8% globally among whom about 90% of cases are type 2 diabetes. There are not any significant clinical manifestations in the primary stages of diabetes. Therefore, screening can be an efficient way to reduce the diabetic complications. Over the recent decades, the prevalence of diabetes has increased alarmingly among the Middle East population, which has imposed exorbitant costs on the health care system in this region. Given that the genetic changes are among the important risk factors associated with predisposing people to diabetes, we examined the role of single-nucleotide polymorphisms (SNPs) in the pathogenesis of diabetes among Middle East population. In the present review, we assessed the molecular pathology of diabetes in the Middle East population that paves the way for introducing an efficient SNP-based diagnostic panel for diabetes screening among the Middle East population. Since, the Middle East has a population of 370 million people; the current review can be a reliable model for the introduction of SNP-based diagnostic panels in other populations and countries around the world.

The Relationship between PTPN22 R620W Polymorphisms and the Susceptibility to Autoimmune Thyroid Diseases: An Updated Meta-analysis

The protein tyrosine phosphatase non-receptor 22 (PTPN22) R620W polymorphism has been related to susceptibility to autoimmune thyroid disease (AITD) with inconsistent results. Therefore, this meta-analysis was designed to assess a more accurate association between the PTPN22 R620W polymorphism and AITD susceptibility. A systematic search of the EMBASE, PubMed, Web of Science, CBM, CNKI, and WanFang databases was performed to determine relevant publications. Statistical analyses of the odds ratios (ORs), 95% confidence intervals (CIs), and p values were performed using STATA software. Our meta-analysis included 18 separate studies comprised of 4,726 cases and 4,220 controls. In the allele and all genetic models, PTPN22 R620W polymorphism and Graves' disease (GD) (allele model TvsC: OR = 1.573; 95% CI = 1.378-1.795; P < .001) and Hashimoto's thyroiditis (HT) (allele model TvsC: OR = 1.737; 95% CI = 1.230-2.454; P = .002) susceptibility was positively associated. A racial subgroup analysis showed that the T allele significantly increased AITD susceptibility in all genetic models involving Caucasians, but not in Asians. This meta-analysis showed that the PTPN22 R620W polymorphism is associated with the risk of GD and HT in the overall study population. In addition, the PTPN22 R620W polymorphism is associated with elevated AITD risk in Caucasians, but not in Asians.

Association of CTLA-4 and CD28 Gene Polymorphisms with Type 1 Diabetes in South Indian Population

Each functional gene illustrates the complexity of genetic predisposition to disease; however, it is difficult to bring out these traits with reference to autoimmune diseases like type 1 diabetes (T1D). To find out the genetic contribution of CTLA-4 + 49A/G, CTLA-4 -318C/T and CD28 + 17T/C polymorphisms toward T1D, the present study was performed with 124 T1D patients, 54 siblings and 125 parents including 39 trios in South Indian population. The association and linkage of CTLA-4 + 49A/G, CTLA-4 -318C/T and CD28 + 17T/C polymorphisms with T1D were analyzed and transmission disequilibrium test was performed. CTLA-4 G allele carrying genotypes (GG+AG) showed a higher risk association and can be considered as susceptible to develop T1D among patients with age at diagnosis from 0 to 10 years as compared to siblings (OR = 2.9; p_c = 0.047) and parents (OR = 2.7; p_c = 0.036). On the other hand, a strong protection against the disease (age at diagnosis; 0-10 years) was observed with CTLA-4 + 49AA genotype (OR = 0.37; p_c = 0.036) and combined AA/CC genotype (OR = 0.31; p_c = 0.034) of CTLA-4 + 49A/G and CTLA-4 -318C/T polymorphisms. However, a significant association was not observed between CTLA-4 -318C/T and CD28 + 17T/C polymorphisms and T1D. This family-based study reports a strong association between possible genotypes of CTLA-4 gene polymorphism and T1D in South Indian population, particularly in younger individuals.