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.
These data suggest that the P2X7R may be involved in the adaptive mechanisms elicited by exposure to repeated environmental stressors that leads to the development of depression-like behaviours.
Being associated with depressive disorders, which have a high risk of suicide, the proteins P11, P2RX7, and S100β may be biomarkers for a suicidal disposition.
No indication for association to depression was found for P2RX7:2230912 and CACNA1C:rs1006737 without or with consideration of childhood problems or negative life events.