GSTT4 (glutathione S-transferase theta 4) is a cytoplasmic Phase II drug-metabolizing enzyme that catalyzes the conjugation of reduced glutathione to hydrophobic electrophiles, facilitating detoxification of exogenous and endogenous compounds 1. As a member of the theta GST family, GSTT4 mediates conjugation of typical GST substrates including 1-chloro-2,4-dinitrobenzene and other xenobiotic compounds, though with variable activity levels compared to other GST isoforms 1. GSTT4 exhibits tissue-specific expression, with detection primarily in testis in primate models 1, and demonstrates sex-dependent expression differences in liver, suggesting potential hormonal regulation 2. While GSTT4 showed nominal association with seizure occurrence in astrocytoma patients, this association did not persist after molecular subgrouping by IDH status, limiting its established clinical significance in tumor-associated epilepsy 3. GSTT4's role in detoxification metabolism positions it as relevant for drug metabolism and xenobiotic responses, though targeted functional characterization of human GSTT4 substrates and clinical disease relevance requires further investigation.