Celiac disease and HLA-DQ genotype: Diagnosis of different genetic risk profiles related to the age in Badajoz, southwestern Spain

Background and objectives: celiac disease is associated with the HLA class II alleles: DQA1*05-DQB1*02 and DQB1*0302. The genetic risk for celiac disease may depend on the presence or absence of such alleles, their combination or number of copies. This study aimed to establish the differences in HLA genotypes between celiac patients diagnosed during childhood and adulthood, and between patients and healthy controls, and to determine the risk of disease in each genotypic category. Methods: we classified 350 celiac patients at time of diagnosis and 218 controls into 14 categories according to their HLA genotype, based on the presence or absence of risk alleles. Results: we found statistically significant differences between the genotype frequencies of celiac patients diagnosed as being children and adults. DQA1*05 (x 1 copy), DQB1*02 (x 1 copy), DQB1*0302 (x 0 copies) was the most frequent genotype in individuals diagnosed in childhood, whereas DQA1*05 (x 1 copy), DQB1*02 (x 2 copies), DQB1*0302 (x 0 copies) was the most frequent in adults. The risk for disease in each genotypic category in celiac children and adults turned out to be different. The presence of DQB1*0302 did not increase risk in children, but did in adults. Conclusion: in our celiac population, we found a different genetic pattern according to age of diagnosis. That could suggest that the pathogenic mechanism of the disease is not exactly the same in both age groups, which could somehow determine clinical presentation of the disease, its epidemiology, coexisting diseases, and complications.