Is HLA-DQ typing useful in screening for celiac disease among Arabs with type 1 diabetes? A case–control study

Abstract

Objectives: The data on the usefulness of DQ-typing in screening for celiac disease (CD) among type 1 diabetic (T1D) patients came from the West. We conducted this study among T1D patients to: (1) determine the frequency of DQ-genotypes, (2) assess the risk associated with human leukocyte antigen (HLA)-DQ genotypes, and (3) identify the cost-effective screening strategy. Methods: HLA-DQ genotyping was performed on 67 T1D patients with CD (cases) (mean age 15 years) and 224 T1D patients without CD (controls) (mean age 18.29 years) (2021–2023). The entry criterion for the control group was duration of T1D ≥5 years and negative annual celiac serology assay. Results: On comparison of the cases versus controls, T1D patients carrying homozygous DQ2.5 genotype (30% vs. 13.8%) or DR3-DQ2.5 haplotype (81.3% vs. 65.7%) showed significantly “higher risk” (odds ratio [OR] = 2.64, p = 0.002; OR = 2.3, p = 0.008, respectively) to develop CD. Only 4% do not harbor any of the CD-at risk genotypes (DQ2.5, DQ8, or DQ2.2) and none developed CD. Heterozygous DQ8 was associated with a significantly lower risk of developing CD with OR of 0.123 (1.5% in cases vs. 10.3% in controls, p = 0.022). Conclusion: Only 4% of Saudi patients with T1D carry DQ-genotypes at no risk to develop CD, which supports the European guidelines that recommend celiac serology test as the most cost-effective screening method. We identified the risk gradient associated with DQ-genotypes to develop CD in our population which could help in counseling patients for the risk to develop CD and planning follow-up serology tests.