GSTT1

GSTT1, or glutathione S-transferase theta 1, is a member of the theta class of cytosolic glutathione S-transferases. It participates in the detoxification of a broad range of electrophilic compounds by catalyzing the conjugation of glutathione to these substrates. In humans, GSTT1 activity contributes to the metabolism of various environmental chemicals and products of endogenous metabolism, helping to protect cells from potential damage.

The GSTT1 gene is located on chromosome 22q11.23. A common genetic variation is a deletion that removes the gene, producing a null allele. Individuals may have two functional copies (present/present), one functional and one deleted (present/null), or two deleted copies (null/null). The frequency of the GSTT1 null genotype varies widely among populations and ethnic groups, reflecting population-specific copy number variation.

GSTT1 is expressed in several tissues, including liver, kidney, and lung, consistent with a role in systemic detoxification. Its contribution to detoxification processes can influence individual susceptibility to toxicants and carcinogens, particularly in conjunction with exposure to tobacco smoke and environmental solvents. Associations between GSTT1 genotype and cancer risk or toxicant-related health outcomes have been reported in epidemiological studies, but results are inconsistent and often depend on interactions with other genetic factors (such as GSTM1) and environmental exposures.

In clinical practice, GSTT1 testing is not routinely used for guiding treatment or risk assessment, though it remains a focus of research in pharmacogenomics and cancer susceptibility. Ongoing studies aim to clarify how GSTT1 genetic variation modulates detoxification capacity and disease risk in diverse populations.