[Association of polymorphism for HLA-DQA1 promotor region (QAP) with IDDM].

We have identified the DNA polymorphism for the HLA-DQA1 promotor region (QAP) in patients with early and late onset insulin-dependent diabetes mellitus (IDDM) by PCR direct sequencing. The result showed that single nucleotide substitution at position-92(C-->T-92) and -146 (T-->C-146) were detected in QAP for early and late onset IDDM respectively. These findings suggests that the mutation seems to alter the conformation of QAP so that these are likely to influence the aberrant expression of MHC-class II loci in beta-pancreatic islet cells.