Moreover, MSRB3 seems to be involved in processes of cell proliferation [67] and synaptic plasticity [68], DPP4 might impact the development of oxidative stress and inflammation, which are both associated with the development of depression [69], and ASTN2 also seems to play a role in synaptic plasticity [70] as well as in neurodevelopmental disorders [71]. Here, DPP4 is linked to major depressive disorder.