ETHNIC-DIFFERENCES IN HUMAN-LEUKOCYTE ANTIGEN MARKERS OF SUSCEPTIBILITY TO IDDM

OBJECTIVE - To determine whether genetic differences explain the lower risk of developing insulin-dependent diabetes mellitus (IDDM) for His panic versus non-Hispanic white children in Colorado. RESEARCH DESiGN AND METHODS - Hispanic (n = 62) and non-Hispanic white (n = 82) subjec ts with IDDM identified from the Colorado IDDM Registry and healthy, n ondiabetic control subjects were recruited. Human leukocyte antigen (H LA) serologic typing and sequence-specific oligonucleotide typing of D QA1 and DQB1 alleles were performed. RESULTS - HLA and allele associat ions with IDDM were similar in both ethnic groups. HLA-DR3 and HLA-DR4 were more common in IDDM subjects in both ethnic groups. Subjects wit h DQB1 alleles encoding aspartic acid (Asp) in position 57 were less l ikely to have IDDM, irrespective of ethnic background. HLA-DR3 was les s common among Hispanic subjects than non-Hispanic white control subje cts (4.4 vs. 17.5%, Hispanics vs. non-Hispanic whites, P = 0.04). CONC LUSIONS - These data suggest that the lower prevalence of HLA-DR3 in t he Hispanic population, a pattern consistent with the presence of Amer indian admixture, may explain the lower rate of IDDM in the Hispanic p opulation.