Distribution of celiac disease predisposing genes HLA-DQ2 and HLA-DQ8 in the native population of southern India.

Background: Celiac disease (CD) is an intestinal inflammatory condition caused by the ingestion of gluten peptides in wheat and related grains in individuals carrying HLA-DQ2 and/or HLA-DQ8 genes. In comparison to HLA-DQ8, a higher HLA-DQ2 prevalence is reported in European population where wheat has been the staple food for thousands of years. In non-European population, this pattern of HLA-DQ CD-predisposing gene distribution has not always been found. The aim of this study was to evaluate the HLA-DQ2 and HLA-DQ8 distribution in the native low-gluten consuming southern Indian population.

Methods: Overall, 211 dried blood spots (DBS) were collected from native southern Indian individuals. HLA-DQ characterization and the determination of homozygous/heterozygous status were performed using commercially available HLA-DQ typing kits.

Results: Of 211 collected DBS, 88 (42%, 95% CI: 36-48) were positive for HLA-DQ2 and/or HLA-DQ8 heterodimers. Overall, 40 (19%, 95% CI: 14-24) samples typed positive for HLA-DQ2 and 48 (23%, 95% CI: 18-28) typed positive for HLA-DQ8 genotypes. Of 40 HLA-DQ2-positive individuals, only one subject tested homozygous for the DQB1*02 allele.

Conclusions: In the southern Indian native general population, the prevalence of HLA-DQ8 is higher in comparison to HLA-DQ2 prevalence. This finding could be related to the delayed introduction of wheat in the diet of the southern Indian population.