Allele-specific gene probing supports the DQ molecule as a determinant of inherited susceptibility to type 1 (insulin-dependent) diabetes mellitus.

Trans-racial analysis of disease associations has improved mapping of MHC-linked susceptibility to Type 1 (insulin-dependent) diabetes mellitus. In this study the contributions of the MHC class II DQA1 and DQB1 genes were investigated. Sequence-specific oligonucleotide gene probing in Type 1 diabetic and control subjects of North Indian origin supported the DQw1.18 allele of the DQB1 gene as a determinant of inherited protection against Type 1 diabetes (RR = 0.12, pc less than 0.05). The A3 allele of the DQA1 gene was positively associated with the disease, (RR = 3.6, pc less than 0.05), as was the DQw2 allele of the DQB1 gene (RR = 4.6, pc less than 0.01). Trans-racial comparison of these disease associations indicates that DQ alleles may directly determine an element of inherited susceptibility to Type 1 diabetes.