HLA-DQ genotypes relative risks for celiac disease in Arabs: A case-control study.

Objective: It remains unknown what degree of risk is conferred by celiac disease (CD)-predisposing human leukocyte antigen (HLA)-DQ genotypes in Saudi Arabia compared with in Western countries. In this study, we aimed to determine the CD risk gradient associated with the HLA-DQ genotypes and to compare HLA-DQ genotypes between symptomatic patients with CD and screening-identified asymptomatic CD patients.

Methods: We enrolled three groups of subjects, including 46 CD children diagnosed consecutively over the past 10 years, 54 CD children diagnosed during a mass screening of schoolchildren, and 192 healthy controls. All the participants were typed for the HLA-DQA1 and HLA-DQB1 genes by polymerase chain reaction sequence-specific oligonucleotide probes.

Results: Comparing the patients with CD to controls, we identified 5 groups in the CD risk gradient: (i) very high risk associated with the DQ2.5/DQ8 genotype (odds ratio [OR] 46.93); (ii) high risk (homozygous DQ2.5, DQ2.5/DQ2.2; OR 4.12-5.04); (iii) intermediate risk (heterozygous DQ2.5, DQ8/DQ2.2; OR 1.61 and 1.67); (iv) low risk (DQ8, DQ2.2); and (v) very low risk (DQ2.x, DQX.5, DQX.x). Heterozygous DQ8 was more common in screening-identified group compared to symptomatic patients (13.0% vs 2.2%); however, other genotypes were very similar between the two groups.

Conclusions: The highest risk of developing CD in our Saudi Arabia population is associated with the DQ2.5/DQ8 genotype.