HLA-DQA1 and -DQB1 alleles in Latino and African American children with diabetes mellitus.

Few studies have described the genetics of childhood diabetes mellitus (DM) in US minorities. High-risk DQA1 and DQB1 alleles (DQA10301, DQB10201, and DQB10302 in African Americans and Latinos, and DQA1 0501 in African Americans) were identified from previous studies and tested in 45 African American and 26 Latino patients from the population-based Chicago Childhood Diabetes Registry, and in 50 healthy race-matched controls. Sixteen of the African American patients and three Latinos had youth-onset type 2 DM and were analyzed separately. In African Americans with type 1 DM, both DQA10102 and DQB10602 were protective (p < 0.0001), and the susceptibility alleles DQA10301 and DQB10201 were more frequent than in controls (p < 0.01). In Latinos, DQA10301 and DQB10302 were marginally increased in patients with DM1 compared to controls; no individual DQA1 or DQB1 allele was protective. Patients with DM1 were significantly more likely to carry one or two high-risk DQA1 alleles in both populations; they were also more likely than controls to carry at least one high-risk DQB1 allele. The odds ratio for the ability to form at least two high-risk DQA1-DQB1 heterodimers (cis and/or trans) was 7.9 (95% CI: 1.7-40.0) for African Americans and 5.7 (1.3-25.6) for Latinos with DM1. African American patients with DM2 were not statistically different from controls, and were less likely to carry four high-risk susceptibility alleles than patients with DM1 (p = 0.002). Many of the HLA-DQ associations previously documented in non-Hispanic White populations also are found in African Americans and Latinos with DM1, although some differences exist.