HLA-DQB1 CODON-57 AND IDDM IN CHINESE LIVING IN TAIWAN

OBJECTIVE - To study the human leukocyte antigen (HLA)-DQB1 genetic ba ckground in the Chinese population in Taiwan and its association with the low incidence of insulin-dependent diabetes mellitus (IDDM) in thi s population. RESEARCH DESIGN AND METHODS - Forty-eight IDDM patients and 59 nondiabetic unrelated control subjects were recruited from the population in Taiwan. HLA-DQB1 exon 2 was enzymatically amplified by p olymerase chain reaction. HLA-DQB1 alleles were diagnosed by dot blott ing and hybridization with 16 sequence-specific oligonucleotide probes . RESULTS - DQB10201 and DQB1*0302 alleles were more frequent and DQB 10301 and DQB1*0601 were less frequent in Chinese with IDDM than in c ontrol subjects. Genotypes for homozygous non-aspartic acid residue (N A/NA) at position 57 were positively associated with IDDM at a relativ e risk of 4.34 (P < 0.001), and those for homozygous aspartic acid (A/ A) were negatively associated with IDDM at a relative risk of 0.14 (P < 0.001). Among the NA/A heterozygotes, only DQB10201/DQB1*0303 was s ignificantly increased in IDDM subjects. CONCLUSIONS - The amino acid residue at position 57 of HLA-DQ P-chain is significantly associated w ith the development or prevention of IDDM in Chinese subjects living i n Taiwan. Other genetic and environmental factors may also play import ant roles in pathogenesis of IDDM.