GENETIC-MARKERS FOR INSULIN-DEPENDENT DIABETES-MELLITUS IN JAPANESE

Although the HLA class II genes are clearly associated with insulin-de pendent diabetes mellitus (IDDM) in all ethnic groups, considerable va riation in the associated haplotypes is observed among the ethnic grou ps. In Japanese, DRB10405-DQA1*0301-DQB1*0401, DRB1*0901-DQA1*0301-DQ B10303 and DRB1+0802-DQA1*0301-DQB1*0302 are the major susceptibility haplotypes to IDDM, while DRB1 1501-DQA1*0102-DQB1* 0602 and DRB1*15 02-DQA10103-DQB1*0601 are the major resistance haplotypes. The hypoth esis that alleles encoding amino acids other than aspartic acid at the DQB1 position 57 contribute to IDDM susceptibility is not applicable to the Japanese, mainly because the first and second susceptibility ha plotypes listed above have aspartic acid at DQB1 position 57. In the 5 ' insulin gene polymorphism, the shorter insertion (class 1 allele) is predominant, and is not associated with diabetes in Japanese. Subdivi sion of the class 1 alleles also failed to show an association with ID DM in Japanese, The insulin gene region appeared to be of less value a s a genetic marker for IDDM in Japanese. Little is known about other g enetic markers.