Association Study of Dysbindin Genotypes with Bipolar I Disorder by Multiple Allele-specific PCR

Bipolar I disorder is a common disorder with a complex etiology. A genetic approach is gaining increasing importance in this disorder. The dysbindin gene، located at 6p22. 3 is considered a susceptibility gene for schizophrenia. Certain genotypes of dysbindin are thought to be associated with other psychoses such as bipolar disorders. This study intends to assess the association in previously implicated dysbindin genotypes and haplotypes with bipolar I disorder in an Iranian population. We genotyped four previously reported SNPs: rs2619522، rs1018381، 2743852 and rs2619538. Their haplotypes were analyzed in a population of 124 patients that consisted of 44 confirmed bipolar I disorder patients and 80 control subjects. We used multiple allele-specific PCR method for genotyping، which was verified by direct sequencing. In concordance with previous reports in other populations our findings showed no association between the single SNPs and bipolar I disorder. Furthermore، none of the alleles showed a significant association with the disorder. In contrast to previous reports، haplotype analysis did not reveal any statistically significant associations with bipolar I disorder. Considering reports of previous studies regarding the implication of these dysbindin genotypes in bipolar I disorder، it is probable that allelic heterogeneity along with lack of an established causal variant in the dysbindin gene can be main factors for this discordance. With regards to ethnicities in other studies، population variation can also be considered an important factor in the observed variation.