The results indicate that there exists possible interrelation between TH and TPH gene expression and epigenetic histone acetylation in CUS-induced depressive rats, which at least partly contributes to the etiology of depression.
Common polymorphisms involved in the tryptophan hydroxylase 1 (TPH1) and 2 (TPH2), serotonin transporter, monoamine oxidase A (MAOA) and brain-derived neurotrophic factor (BDNF) were investigated in a naturalistic inpatient study of the German research network on depression.
To investigate the possible relationship between genetic risk factors and depression in AD, we assessed genetic polymorphisms reported to be associated with depression (MAOA VNTR, ACE 288bp Insertion/ Deletion, 5HTTLPR, COMT Val158Met, BDNF Val66Met, TPH1 A218C, HTR2A T102C, P2RX7 Q460R, FKBP5 rs1360780 and CRHR1 rs242941) in a cross-sectional study on 246 AD patients with or without clinically significant major depressive disorder (MDD) according to DSM-IV.
Two functional polymorphisms of the serotonin transporter gene, 5-HTTLPR and STin2 have been investigated in a large number of pharmacogenetic studies of depression; other candidate genes include serotonin receptor genes, brain-derived neurotrophic factor, P-glycoprotein (located in the blood-brain barrier), G-proteins, TPH1 and TPH2, MAOA, the noradrenaline transporter gene, FKBP5, or cytochrome P450 (CYP450) genes.