Human leukocyte antigen alleles in patients with bipolar disorder in the Korean population

We performed an association study between human leukocyte antigen (HLA) alleles and bipolar disorder to evaluate the potentiality of HLA as a genetic marker in bipolar disorder. HLA class I and class II allele frequencies were assessed in 87 bipolar patients and were compared with those of 206 normal controls in the Korean population. HLA class I typing was performed using the microlymphocytotoxicity method, whereas class II (DRB1 and DQB1) genotyping was performed with polymerase chain reaction-sequence specific oligonucleotide probes. When the allele frequency of HLA in bipolar patients was compared with that in normal controls, there were some significant differences. Bipolar patients showed statistically significant increased allele frequencies of HLA-A29 and B54. Allele frequencies of HLA-B51 and DRB1*02 were significantly higher in normal controls. However, these results were no longer significant after correcting for the number of alleles. The results of the present study suggest that HLA alleles may not confer susceptibility to bipolar disorder in the Korean population. To clarify the genetic influence of HLA on bipolar disorder, we should conduct a consecutive study with a larger cohort of subjects.