Non-HLA genetic factors and insulin dependent diabetes mellitus in the Japanese: TCRA, TCRB and TCRG, INS, THY1, CD3D and ETS1.

Polymorphism of the genes encoding the alpha, beta, and gamma chains of the human T-cell receptor (TCRA, TCRB, and TCRG), insulin gene (INS), and three closely linked polymorphic genes on chromosome 11q23, Thy-1 (THY1), T3-D (CD3D), and c-ets proto oncogene (ETS1) were investigated among 56 unrelated patients with insulin-dependent diabetes mellitus (IDDM) and 48 healthy controls. Only eight of the 17 enzymes examined revealed restriction fragment length polymorphism (RFLP), with the use of TCRA, TCRB, and TCRG. No significant association was observed. Polymorphism after BglI, SstI, and TaqI digestion was observed for the INS gene. In consideration of the three classes within the insulin-gene-linked DNA polymorphism alleles, A1 and more rarely A2 alleles were found, but with no significant frequencies. THY1 and CD3D genes were polymorphic after MspI digestion but no significant association was observed. Conversely, the ETS1 gene showed polymorphism after TaqI, SstI, and AvaII were used. Only a significant AvaII-polymorphic fragment (p less than 0.03) was found. However, this significant association disappeared when the correct p value was applied. These results were compared to findings in Caucasians and some differences were noted. The polymorphism observed in this study may be useful in genetic studies on immunologically affected populations.