Reevaluation of human leukocyte antigen DR-DQ haplotype and genotype in type 1 diabetes in the Japanese population.

AIM: This study aims at clarifying the human leukocyte antigen haplotypes and genotypes conferring susceptibility or resistance to type 1 diabetes in the Japanese population. METHODS: The frequencies of human leukocyte antigen DR-DQ haplotypes and genotypes were compared between 83 type 1 diabetic patients, except for fulminant type 1 diabetes, and control subjects in the Japanese population. The patients were divided by onset age into four groups (ages 5-14, 15-29, 30-49, and 50-71 years); the haplotype frequency was compared between each group. RESULTS: The frequencies of DRB1*0405-DQB1*0401 (DR4), DRB1*0802-DQB1*0302 (DR8), DRB1*0901-DQB1*0303 (DR9), and DRB1*1302-DQB1* 0604 (DR13) haplotypes were significantly higher in the patients than in the control subjects. The frequencies of DRB1* 1501-DQB1*0602 and DRB1*1502-DQB1*0601 haplotypes were significantly lower in the patients than in the controls. The frequencies of DR4/8, DR4/13, DR9/9, and DR9/13 genotypes were significantly higher in the patients than in the control subjects. The DR13 haplotype was the most frequent haplotype in the age group 30-49 years, whereas the other haplotypes but DR13 were the most frequent in the other age groups. CONCLUSION: DR4, DR8, DR9, and DR13 haplotypes confer susceptibility to type 1 diabetes in Japanese patients.