HLA alleles and IDDM in children in Hungary: A comparison with Finland

It has been postulated that variation in the distribution of human leukocyt e antigen (HLA)-encoded susceptibility alleles for insulin-dependent diabet es mellitus (IDDM) is the genetic basis for variation in the incidence of t he disease between populations, The aim of this study was to characterize H LA-encoded susceptibility to IDDM in Hungary and to identify whether HLA-DR B1/DQ-encoded susceptibility could account for the five times lower inciden ce of disease in Hungary compared with Finland. The haplotypes DRB1*03-DQA1 *05-DQB1*02 (DRBl*03-DQ2) and DRB1*04-DQA1*0301-DQB1*0302 (DRB1*04-DQ8) wer e significantly associated with disease in both populations. Three genotype s incorporating either or both of these haplotypes accounted for over 70% o f the diabetic population in both races. The combined background frequency and the degree of risk as measured by odds ratios of these HLA-DRB1-DQ geno types were not significantly different in the two countries. Comparison of the DRB1*0401-DQ8 haplotype between the two races suggested a role for HLA- B alleles in susceptibility. These data indicate that the susceptibility as sociated with high risk DRB1-DQ genotypes alone is insufficient to account for the fivefold variation in incidence of IDDM between Hungary and Finland . Other generic and/or environmental influences must be involved. (C) Ameri can Society for Histocompatibility and Immunogenetics, 2001, Published by E lsevier Science inc.