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Article Type

Original Study

Abstract

Objective The aim of the study was to investigate the distribution of cytotoxic T-lymphocyte antigen-4 (CTLA-4) (+49A/G) gene variants and its association with type 1 diabetes (T1D) in Egyptian children. Background T1D is a complex autoimmune disease characterized by T-cell-mediated destruction of the pancreatic island. Human leukocyte antigen (HLAs) account for about 60% of genetic susceptibility for the disease. About 20 non-HLA loci contributing to disease susceptibility have been identified. One among these is the CTLA-4 gene. CTLA-4 polymorphisms are associated with T1D in some but not all populations. The aim of our study was to investigate the frequency of CTLA-4 49A/G polymorphism in Egyptian children, and its susceptibility for development of T1D. Materials and methods A case-control study was conducted on 40 Egyptian children with T1D diagnosed according to ADA (2010). Their ages ranged from 1 to 16 years, with a mean of 8.76 ± 4.70 years; 15 were male and 25 were female. In addition, 20 age and sex-matched healthy controls were included. CTLA-4 (+49A/G) gene polymorphism typing was done by PCR amplification, followed by restriction fragment length polymorphism. Results The frequency of CTLA-4 polymorphisms (AA, AG, and GG) in T1D patients was 42.5, 52.5, and 5% versus 60, 40, and 0% in controls, respectively, with predominance of the AG variant in diabetic patients. Distributions of the CTLA-4 gene polymorphism on the basis of sex showed a normal pattern. The AA genotype was present in 64.7% of female diabetic patients versus 35.3% of male patients, whereas the heterozygous AG genotype was seen in 57.1% of female patients versus 42.9% of male patients, and the homozygous GG genotype was present in two female patients (5%) and was not recognized in male patients; the female predominance can be explained by steroid hormone association. Conclusion In this study the overall pooled prevalence of the CTLA4 (+49A/G) polymorphism was recognized but still not a risk susceptibility factor for T1D in Egyptian children.

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