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 (DQA1*0301, DQB1*0201, and DQB1*0302 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 DQA1*0102 and DQB1*0602 were protective (p < 0.0001), and the susceptibility alleles DQA1*0301 and DQB1*0201 were more frequent than in controls (p < 0.01). In Latinos, DQA1*0301 and DQB1*0302 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.