Significant ethnic differences may be observed in terms of biological markers in different psychiatric illnesses. The HLA system, which is a genetic marker in mood disorders, is such a case. Related research suggests that the genes located on the HLA region of the sixth chromosome may be one of the various factors that contribute to the etiology of mood disorders. It has been reported that there is a significant increase in HLA B16, HLA A29, and B21, HLA-B7 frequencies in patients with bipolar disorders [1,4,5]. However, others did not observe a relationship between HLA haplotypes and mood disorder [3,6]. We investigated the relationship between bipolar mood disorder and HLA antigens by studying a rather large and ethnically homogenous group.

Fifty (24 women and 26 men) patients diagnosed as bipolar mood disorder type I according to DSM-IV criteria were included in the study. The average numbers of manic episodes and depression episodes were 4.2 (SD = 1.4) and 2.1 (SD = 1.1), respectively. Furthermore, a control group of 100 people having no previous or present mental illnesses under examination as donors for kidney transplantation was formed. Written informed consent was obtained from all the subjects. There was not any difference between the two groups in terms of sex and age.

The blood samples were analysed according to the microlymphocitotoxicity method Reference Jun, Pae, Chae, Pyo and Han[2]. The loci examined were HLA A (A1-3, A11, A23-26, A28-34, A43, A66); B (B7, B8, B13, B14, B18, B27, B35, B37-42, B44-47, B49-59, B62, B63, B67, B70, B73); C (Cw1, Cw3-6); DR (DR1, DR15-18, DR4, DR11-14, DR7-10, DR51-53, DQ1, DQ2, DQ4, DQ7). HLA DQ8 and DQ9 antigens could not be examined serologically. All the patients and controls were Caucasian and of Turkish origin. In intergroup comparison, the HLA-B7 (χ ² = 3.64, df = 1, p = 0.05), HLA-DR 11 (χ ² = 4.83, df = 1, p = 0.04) and HLA-DQ7 (χ ² = 5.39, df = 1, p = 0.03) antigens were found to be more frequent in the bipolar patient group. However, these results were no longer significant after correcting for the number of alleles. Our findings suggest that HLA alleles may not confer susceptibility to bipolar disorder in the Turkish population.