GSTT1null

GSTT1null refers to the homozygous deletion of the GSTT1 gene, resulting in no functional theta class glutathione S-transferase 1 enzyme. The GSTT1 gene is part of the glutathione S-transferase family, enzymes that detoxify electrophilic compounds and products of oxidative stress by conjugating them to glutathione. The absence of GSTT1 activity can alter the body's capacity to process certain environmental and endogenous toxins.

Genetic variation in GSTT1 is common among humans. Individuals can carry a present allele (functional copy) or a null allele (deletion). GSTT1 null is inherited in an autosomal manner, and its frequency varies by ethnicity and population. Detection is typically performed with PCR-based genotyping on blood or cheek swab samples, reporting results as GSTT1 present or GSTT1 null.

Clinical relevance has been explored in relation to disease risk and drug response. In epidemiological studies, GSTT1null has been investigated for associations with cancer risk (including liver, bladder, and breast cancers) and with adverse effects from environmental exposures such as tobacco smoke and aflatoxins. Findings are inconsistent and often context-dependent, influenced by coexisting genetic factors (such as GSTM1 status) and environmental exposures. Consequently, GSTT1null is not a universally accepted clinical biomarker.

In research and pharmacogenomics, GSTT1null status has been used to study detoxification pathways and gene–environment interactions. However, it has not, in general, become a standard determinant for clinical decision-making or treatment guidelines.