NCAM1, TACR1 and NOS genes and temperament: a study on suicide attempters and controls.

Suicide, one of the leading causes of death among young adults, seems to be plausibly modulated by both genetic and personality factors. The aim of this study was to dissect the potential association between genetics and temperament in a sample of 111 suicide attempters and 289 healthy controls. We focused on 4 genes previously investigated in association with suicide on the same sample: the nitric oxide synthase 1 and 3 (NOS1 and NOS3), the neuronal cell adhesion molecule 1 (NCAM1), and the tachykinin receptor 1 (TACR1) genes. In particular, we investigated whether a set of genetic variants in these genes (NOS1: rs2682826, rs1353939, rs693534; NOS3: rs2070744, rs1799983, rs891512; NCAM1: rs2301228, rs1884, rs1245113, rs1369816, rs2196456, rs584427; TACR1: rs3771810, rs3771825, rs726506, rs1477157) were associated with temperamental traits at the Temperament and Character Inventory (TCI). No strong evidence was found for the association between TCI personality traits and the polymorphisms considered in the 4 genes, with the exception of an association between reward dependence trait and the rs2682826 SNP in NOS1 in the healthy sample. However, this result could be plausibly interpreted as a false-positive finding. In conclusion, our study did not support the thesis of a direct modulation of these genes on temperament; however, further studies on larger samples are clearly required in order to confirm our preliminary findings and to exclude any possible minor influence.