HLA-DQ genotypes - but not immune markers - differ by ethnicity in patients with childhood onset type 1 diabetes residing in Belgium.

AIM

The aim of this study was to compare genetic (HLA-DQ) and immune markers in a large population of type 1 diabetic (T1D) children and adolescents residing in the same environment, but of different ethnic origin: European Caucasians (EC), Moghrabin Caucasians (MC), Black Africans (BA) and of Mixed Origin (MO).

METHODS

Retrospective study, including 452 patients with T1D aged 0.1-17.5 yr at diagnosis recruited at the Diabetology Clinic of the University Children's Hospital Queen Fabiola from May 1995 to March 2013. HLA-DQ genotyping, diabetes-associated autoantibodies, organ-specific autoantibodies, and other markers of autoimmunity were studied.

RESULTS

The proportion of the different ethnic groups was: 55% EC, 35% MC, 6% BA, and 4% MO. Between these four groups, there were no significant differences concerning age, hemoglobin A1c (HbA1c), presence of diabetic ketoacidosis, random C-peptide level at diagnosis and 2 yr later. The two most frequent haplotypes were DQA10501-DQB10201 and DQA10301-DQB10302 with a significant higher prevalence in MC and EC (p = 0.002 and 0.03, respectively). The high-risk heterozygous genotype DQA10301-DQB10302/DQA10501-DQB10201 was more frequent in EC than in MC, whereas the homozygous genotype DQA10501-DQB10201/DQA10501-DQB10201 was more prevalent in MC (p = 0.019). These susceptible genotypes were more frequent in youngest patients (p = 0.003). Diabetes-associated autoantibodies, organ-specific autoantibodies, and other immune markers did not statistically differ between ethnic groups.

CONCLUSIONS

These observations in a large population of T1D children and adolescents of different ethnic groups residing in Belgium show significant differences in HLA-DQ status, but not in diabetes-associated autoantibodies, organ-specific autoantibodies, or other immune markers.