Objective: To clarify whether there is an association of insulin-dependent diabetes mellitus (IDDM) susceptibility with HLA-DQA1 locus in adult-onset IDDM.
Patients and methods: Possible heterogeneity in immunogenetic aspects was investigated by comparing the findings on relationship between HLA-DQA1 52 Arg(+) and IDDM predisposition in three groups with different ages of IDDM onset (group A 14 years, group B 15-30 years, group C > 31 years).
Results: The frequency of HLA-DQA1 52 Arg(+) in group A (87.5%) was higher than that in control (53.9%, P < 0.05) and in group B and C (P < 0.05). The frequency of HLA-DQA1 52 Arg(+)/Arg(+) phenotype in group A (75%) was higher than that in group C (23.1%, P < 0.05).
Conclusion: The contribution of HLA-DQA1 52 arginine to IDDM susceptibility is heterogeneous. Further study is necessary to clarify the immunogenetic entity of IDDM.