Genetic susceptibility for celiac disease is highly prevalent in the Saudi population

Background/Aim: To determine the frequency of celiac disease (CD)-predisposing human leukocyte antigen (HLA)-DQ genotypes in the Saudi population, where the prevalence of CD is 1.5% as recently reported in a mass screening study. Patients and Methods: In a cross-sectional population-based study, a total of 192 randomly selected healthy school children (97 females, mean age 10.5 +/- 2.2 years, all negative for tissue transglutaminase-IgA) were typed for DQA1 and DQB1 genes by polymerase chain reaction sequence-specific oligonucleotide probes. Results: Of the 192 children, 52.7% carried the high-risk CD-associated HLA-DQ molecules: homozygous DQ2.5 (2.6%), DQ2.5/DQ2.2 (4.7%), heterozygous DQ2.5 (28.15%), homozygous DQ8 (4.2%), DQ8/DQ2.2 (3.6%), and double dose DQ2.2 (9.4%). Low-risk CD-associated HLA-DQ molecules (single dose DQ2.2 and heterozygous DA constituted 3.6% and 9.4%, respectively. Among the very low-risk groups, individuals lacking alleles that contribute to DQ2/DQ8 variants (33.5%), 13.5% carried only one of the alleles of the high-risk HLA-DQ2.5 heterodimer called "half-heterodimer" (HLA-DQA1*05 in 12% and HLA-DQB1*02 in 1.5%), and 20.8% lacked all the susceptible alleles (DQX.x). Gender distribution was not significantly different among the CD-risk groups. Conclusion: We report one of the highest frequencies of CD-predisposing HLA-DQ genotypes among healthy general populations (52.7%) worldwide, which might partly explain the high prevalence of CD in the Saudi community