PTGS1 and major depressive disorder: Three candidate genes implicated in anxiety and depression were selected: Htr2b29 (encoding the Serotonin receptor 2b), Cacna1c30 (encoding the α1C subunit of the voltage-gated L-type calcium channel Cav1.2) and Ptgs1 (encoding a prostaglandin-synthesising enzyme Cyclooxygenase-1).