The protein levels of 5-HT1AR and NUDR, which regulate 5-HT signaling, in the prefrontal cortex were found to be lower in MDD women than in control subjects; however, this difference was not observed in MDD males compared with controls.453 The NA/NE system, especially in the LC, is another monoaminergic system that exhibits sex-related variations and influences MDD risk. Here, DEAF1 is linked to major depressive disorder.