Wigner et al. investigated SNVs of SOD2, CAT, GPx4, and NOS1 genes (see Section 2.1.2 on “Depression and Bipolar Affective Disorder” regarding NOS1)and NOS2 SNVs c.−227G>C(rs10459953) and c.1823C>T(p.Ser608Leu)(rs2297518) in 281 depressed patients in comparison with 299 controls of the Polish population. Here, GPX4 is linked to major depressive disorder.