HLA class II immunogenetics of IDDM in Yemenite Jews.

The association between HLA-DR and DQ and insulin dependent diabetes mellitus (IDDM) was analyzed in 47 patients and 76 controls of Yemenite Jewish origin. The IDDM susceptibility alleles DRB103011, DQA10501, DQB102 and DRB10402, DQA10301, DQB10302 found in Caucasians had a very strong predisposing effect also in the Yemenite IDDM group. The DRB107, DQA10201 and DQB102 alleles were found to have a strong negative association with IDDM. None of the patients carried DRB107 and DQA10201 compared with healthy controls (43.7%). Our analysis revealed that the DRB103011 DQA10501 DQB102/DRB104 DQA103 DQB10302 heterozygous genotype confers the highest susceptibility (59.6% in patients vs. 0% in controls). The homozygous DRB103 and DRB104 genotypes were also found to be positively associated with the disease. 81% of the patients compared to 1.3% of controls carried the susceptibility alleles on both haplotypes. In conclusion, the development of IDDM in Yemenite Jews is strongly dependent on the presence of the susceptibility HLA alleles and on the absence of the DRB107 haplotype. The Yemenite Jewish group is uniquely homogenous with regard to genetic susceptibility factors involved in the process of IDDM, and may thus be an ideal model for further genetic studies.