HLA-DQ2 gene association with Celiac disease in Babylon province, Iraq

Document Type : Research Paper

Authors

Al-Qasim Green University, College of Biotechnology, Department of Applied Biotechnology, Babylon 51013, Iraq.

10.22103/jab.2026.26571.1828

Abstract

Objective
Celiac disease is one of the most common autoimmune disorders caused via gluten consumption of genetically susceptible individuals. This disease causes damages the small intestine through immune response. The main genetic risk factors are HLA-DQ2 and HLA-DQ8 genes, along with exposure to gluten. This study aimed to examine genetic and immunological markers of celiac disease in patients from Babylon Province. It compared age distribution between patients and healthy controls, tested for anti-gliadin IgG and IgA antibodies using ELISA, and checked for the presence of the HLA-DQ2 gene using conventional PCR in both groups.
Materials and methods
Blood samples were collected from patients and healthy controls. Venous blood (3 mL in EDTA tubes for DNA extraction and 2 mL in gel tubes for serology) was drawn from each participant. Samples were transported in a cooling box within 2 to 24 hours and stored at 4°C until analysis. Serological tests detected anti-gliadin IgG and IgA antibodies by ELISA. Genomic DNA was extracted from blood for molecular analysis using conventional PCR to identify the HLA-DQ2 gene. Gel electrophoresis confirmed PCR products, with band size compared to a DNA ladder.
 
 
Results
Conventional PCR showed the HLA-DQ2 gene fragment at approximately 153 bp. In celiac disease patients, the homozygous HLA-DQ2 genotype was the most common, present in 77.2% (14 out of patients tested). The remaining patients lacked this gene, likely due to following a strict gluten-free diet. In the control group, no one carried the HLA-DQ2 gene (0%). Studies demonstrated that HLA-DQ2 homozygosity carries the highest risk, that increase the possibility of early-onset celiac disease in children by 5 to 30 times in comparison to lower-risk genotypes like HLA-DQ8 homozygosity or HLA-DQ2/DQ8 heterozygosity. HLA-DQ2/DQ8 heterozygotes have a lower risk, with only about 3% developing the disease in spite of a 25-35% frequency in the general population. Thus, HLA-DQ2 homozygosity represents most frequent genotype among celiac disease patients.
Conclusion
Molecular genetic testing plays an important key role in identification of individuals who are at risk of celiac disease. Current study found that the homozygous of HLA-DQ2 genotype is the most common of celiac disease patients in Province of Babylon, in which highlight its strong association with the disease. These findings support the use of genetic screening alongside serological tests for better diagnosis and management.

Keywords

References

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Agricultural Biotechnology Journal
Volume 18, Issue 3
June 2026
Pages 123-136

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