Genetic contribution of the BAT2 gene microsatellite polymorphism to the age-at-onset of insulin-dependent diabetes mellitus.

Abstract

The BAT2 gene lies within the class III region of the major histocompatibility complex. We investigated the frequency of the BAT2 microsatellite alleles (BAT2) in 74 young-onset insulin-dependent diabetes mellitus (IDDM) patients, 51 adult-onset IDDM patients, and 85 normal control subjects, and assessed the associations among these BAT2 alleles, TNFa microsatellite alleles (TNFa), and HLA-DRB1 alleles. The frequency of the BAT2.9 allele was significantly increased in the young-onset IDDM patients (12.8 vs 4.1%, Pc=0.04896), whereas the frequency of BAT2.12 allele was significantly decreased in young-onset IDDM patients (0.0 vs 11.8%, Pc=0.00002) compared with control subjects. The BAT2.9 allele was strongly associated with TNFa9 in the young-onset IDDM patients, although no association was found between the BAT2.9 and HLA-DRB1 alleles. The BAT2.12 allele was strongly associated with TNFa13, and with DRB1*1502 in control subjects. These results suggest that the BAT2 microsatellite polymorphism is associated with the age-at-onset of IDDM and possibly with the inflammatory process of pancreatic beta-cell destruction during the development of IDDM. However, this association is not independent of TNFa polymorphisms.