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.
The aim of this study was to investigate the role of serotonin in depression, searching for association of two serotoninergic polymorphisms (T102C of serotonin receptor 5-HT2A and serotonin transporter linked polymorphic region -5-HTTLPR- of SLC6A4 gene) with depressive symptoms and considering their possible interactions with Apolipoprotein E (ApoE) and between themselves, in a sample of 208 sporadic AD patients and 116 normal controls from Italy.
Associations between suicidal ideation and 5-HTTLPR, STin2 VNTR, 5-HTR2a 1438A/G, and 5-HTR2a 102T/C genotypes were estimated using logistic regression models, and gene-gene interactions were investigated using the generalized multifactor dimensionality reduction method after adjustment for potential covariates, including depression.
5-HT2A receptor gene polymorphism rs6313 was associated with 5-HT2A receptor binding potential, with the ability of individuals to use environmental support in order to prevent depression, and with sleep improvement after antidepressant treatment with mirtazapine.