The human leukocyte antigen HLA DRB3*0202/DQA1*0501 haplotype is associated with Graves' disease in African Americans

Information on genetic susceptibility to Graves' disease in African America ns is limited. We studied DRB1, DQB1, DRB3 subtypes, DQA1*0501, DQA1*0201, and CTLA-4 polymorphisms in 49 African American patients with adult onset G raves' disease and 47 racially-matched controls using PCR-based sequence-sp ecific priming methods. There were no significant differences in DRB1 or DQ B1 allelic frequencies or CTLA-4 polymorphisms between patients and control s. However, we found that the frequency of DRB3 was significantly increased in the patients (75.5% vs. 57.4%, P = 0.006, X-2 = 5.52), especially for t he DRB3*0202 subtype (53.1% us. 23.4, P = 0.003, X-2 = 8.91). In this one r espect, the finding was in concordance with our previous observations in Ca ucasian patients with adult-onset Graves' disease. In addition, whereas the frequency of DQA1*0501 was increased (P = 0.018, X-2 = 5.63) in our patien ts, the haplotype of DRB3/DQA1*0501, or DRBS*0202/DQA1*0501 was found to be more strongly associated (P = 0.008, X-2 = 7.0; P = 0.0008, X-2 = 11.34, r espectively). These data suggest that DRB3*0202, particularly when found wi th DQA1*0501 in a haplotype is a susceptible gene(s) for Graves' disease in adult African Americans. Considering these data with those in Caucasian pa tients, our results would suggest that the primary Graves susceptible locus is likely DRB3 and not DRB1.