Association of CTLA-4 (rs231775) and FOXP3 (rs3761548) Gene Polymorphisms with Type 1 Diabetes in Iraqi Kurdish Children

Objective: The objective of the current research was to determine the correlation between FOXP3 (rs3761548) and CTLA-4 (rs231775) gene polymorphisms and Type 1 Diabetes susceptibility among children of the Iraqi-Kurdish population. Methods: A total of 140 pediatric participants (70 with T1D and 70 age- and sex-matched controls) were recruited in this study. Whole blood taken at the periphery was subjected to genomic DNA extraction using the Qiagen DNA Extraction Kit (Qiagen, Hilden, Germany). Amplification of the specific genomic regions containing the target polymorphisms CTLA4 rs231775 and FOXP3 rs3761548 was performed through polymerase chain reaction (PCR). The presence of the PCR product and the amplicon size was confirmed using the QIAxcel Advanced System (QIAGEN GmbH, Hilden, Germany). The confirmed products were then sent for Sanger sequencing. Results: The CTLA-4 rs231775 variant was statistically significant at the genotype level (P = 0.039) and under the dominant inheritance model (P = 0.017); the allele G seemed to have a higher frequency in the patients. In contrast, a sex-stratified analysis across the X-linked FOXP3 3761548 polymorphism showed no statistically significant association with T1D either female or male subjects. Conclusions: The current study demonstrates that the CTLA 4 rs231775 polymorphism, specifically the AG genotype and G allele is correlated with the susceptibility to T1D in the children of Iraqi Kurdish population, but the X-linked FOXP3 variant is not statistically significant.