The HTR2A gene codes for a serotonin receptor and is associated with behavioral traits, schizophrenia and depression [64], KCNAB3 encodes a subunit of a voltage-sensitive potassium channel, and SPNS1 codes for the Spinster-1 protein implicated in apoptosis in the Drosophila central nervous system [65, 66]. Here, KCND2 is linked to major depressive disorder.