Associations between insulin-dependent diabetes mellitus and HLA-DQA1 alleles

Abstract

The incidence of HLA-DQA1 alleles was assessed in patients with insulin-dependent diabetes mellitus (IDDM), their relatives, and healthy controls using HLA-DQA1 genotyping by digestion of PCR amplified DNA with allele-specific restriction enzymes. A significant increase in the incidence of HLA-DQA1*0301 allele was observed in diabetics although the ratio of DQA1*0301 homozygotes to heterozygotes was similar in the patients and controls. The presence of one DQA 1*0301 allele in the genome appeared to be sufficient for susceptibility to IDDM. Comparison of the incidence of other DQA1 "Arg52" alleles in diabetics and healthy controls revealed no differences between the groups. The incidence of DQA1 "non-Arg52" alleles (specifically DQA1*0201) was reduced in diabetics as compared to normal controls. The presence of these alleles may be considered as the "protective" factor.