Bipolar disorder (BD) and schizophrenia (SC) are common and severe psychiatric disorders. There have been various studies regarding the pathophysiological mechanisms of both disorders, although the etiologies are still unknown.
One of the several candidate genes involved in the pathogenesis of both disorders is dopamine D1 receptor (DRD1), especially its function in the prefrontal cortex. It is also reported that the adenosine neurotransmission systems affect the functions of dopaminergic ones.
In addition, several lines of evidence have been suggesting that both disorders have common genetic background.
In our previous studies, we reported that the adenosine A1 receptor (ADORA1) may be genetically associated with SC, which might share the same molecular basis with BD.
Therefore, it is possible to hypothesize that the functions of ADORA1 and DRD1 are involved in the pathophysiological mechanisms of these disorders. To clarify the genetic relationship between these receptors and diseases, we carried out the association study using the Japanese population.
Eight SNPs (5 SNPs of ADORA1 gene indicating statistical significant tendency and 3 SNPs of DRD1 gene) were genotyped by Taqman real-time PCR method. Association analysis of each polymorphism was performed.
The result showed that one SNP of ADORA1 gene and two SNPs of DRD1 gene indicated statistically significant difference between the BD patients and controls and one SNP of DRD1 gene also indicated statistical significance between the SC patients and controls.
However, after Bonferroni correction, these statistical differences were disappeared.The results will be discussed.
The further analysis is in progress.