GPX6 is a selenium-containing glutathione peroxidase that functions in cellular redox homeostasis. As a selenoprotein, it catalyzes the reduction of hydroperoxides to alcohols using glutathione as a cofactor, contributing to antioxidant defense mechanisms. GPX6 evolved specifically in placental mammals through duplication of GPx3, though it has undergone independent losses of selenocysteine in some lineages 1. In humans, GPX6 expression is notably restricted to the olfactory system 2, and its precise biological functions remain largely unknown despite its inclusion among the eight identified mammalian glutathione peroxidases 3. GPX6 has been associated with multiple disease contexts. Genome-wide association studies identified GPX6 variants at 6p22.1 as specifically associated with serous epithelial ovarian cancer risk 4. In breast cancer susceptibility, polymorphisms in GPX6 (rs406113 and rs974334) showed significant associations, with epistatic interactions among GPX6 variants and polymorphisms in other oxidative-stress genes conferring increased breast cancer risk in Spanish populations 5. Additionally, GPX6 expression is modulated in metabolic disease contexts; hepatic GPX6 expression increased in high-fat, high-fructose diet models and decreased under methionine-choline-supplemented conditions 6. GPX6 variants have also been linked to neurodevelopmental and neuropsychiatric conditions including intellectual disability and autism, though the mechanisms underlying these associations require further investigation.