PREVALENCE OF HLA-DQ BETA CHAIN NON-ASP ALLELES IN TYPE I (INSULIN-DEPENDENT) DIABETICS WITH YOUNG AND OLDER AGES OF ONSET

Particular HLA-DQβ chain alleles were reported as immunogenetic markers of type I diabetes mellitus with young onset of the disease. In a homogenous German population, we studied HLA-DR specificities and HLA-DQβ chain alleles in young-onset ( 40 years of age;n=48) insulin-dependent diabetics. In both cohorts of type I diabetics, the HLA-DR3 and -DR4 specificities were significantly increased. The presence of an HLA haplotype with an amino acid other than aspartic acid at position 57 of the DQβ chain was significantly associated with type I diabetes in both cohorts (etiologic fraction:93% and 73%). We conclude that the presence of DNA sequences coding for an amino acid other than aspartic acid at the 57th position of the DQβ chain provides a molecular risk marker for type I diabetes of both and adult onset.