Analysis of HLA-DQA1 in Japanese patients with type 1 diabetes mellitus, using DNA-PCR-RFLP typing.

DNA-polymerase chain reaction(PCR)-RFLP(restriction fragment length polymorphism) typing of the DQA1 gene was performed on 39 patients with type 1 diabetes and 30 controls. Analysis of the frequency of the subtypes of DQA1 alleles, using the DNA-PCR-RFLP typing technique, showed that the DQA10301 subtype was most strongly associated with the disease (97.4% vs 56.7%, R.R. = 19.8, pc less than 0.00005). These results indicated that DQA10301 may determine the disease susceptibility in the Japanese. In addition, we analyzed the frequency of the subtypes of DQA1 genes in the ten patients carrying the DRW8-DQW8 haplotype, and found that at least eight of them (80%) were classified as having DQA10301. The DRW8-DQW8-DQA10301 may be one of the susceptible haplotypes among the Japanese.