HLA-DR and -DQ associations with insulin-dependent diabetes mellitus in a population of Turkey

Genetic susceptibility to insulin-dependent diabetes mellitus (IDDM) has be en shown to be associated with MHC in many studies. To extend this data wit h a population with relatively low IDDM incidence, MHC DRB, DQA, and DQB ha ve been investigated by polymerase chain reaction and sequence specific oli gonucleotide probe hybridization (PCR/SSO) in 178 IDDM patients from Turkey and compared to 248 healthy controls. Significant differences are detected between IDDM and control groups in the frequencies of DRB1*0402 DQA1*03 DQ B1*0302 (28.1% vs. 5.2%, p < 0.0001, OR: 7.1) and DRB1*0301 DQA1*0501 DQB1* 02 (57% vs. 18.1% p < 0.0001, OR: 6.1). Among the negative associations, th e most strong ones are with DRB1*1401 DQA1*0101 DQB1*0503 (0.6% vs. 8.9%, p < 0.0001, OR: 0.1), DRB1*1502 DQA1*0103 DQB1*0601 (1.1% vs. 7.7%, p = 0.00 23, OR: 0.1), DRB1*1301 DQA1*0103 DQB1*0603 (0.6% vs. 6.9%, p = 0.0039, OR: 0.2) and DRB1*1101 DQA1*0501 DQB1*0301 (3.9% vs. 12.1%, p < 0.0001, OR: 0. 2) When the DRB, DQA or DQB genotypes of the susceptible alleles are compar ed, the most strong susceptibility marker of the disease is found to be DRB 1*0301/*04 (31.4% vs. 2.8%, p < 0.0001, OR: 15.8) and among these, heterozy gote genotype DRB1*0301/*0401 (4.5%; vs. 0, p = 0.0008, OR: 24.8). These results confirm the positive associations with IDDM previously observ ed in other Caucasian populations and reveal many negative and strong assoc iations which maybe underlining several characteristics that distinguish Tu rkish diabetics furm form Caucasians. (C) American Society for Histocompata bility and Immunogenetics, 2000. Published by Elsevier Science Inc.