Does the GPX4 rs713041 C/T genotype alter the selenoprotein response to selenium intake?

The GPX4 rs713041 polymorphism (also known as c718t) is a significant genetic variant that dictates how an individual’s cellular antioxidant system responds to selenium. This single nucleotide polymorphism (SNP) is located within the 3′ untranslated region (3′UTR) of the GPX4 gene, specifically inside the Selenocysteine Insertion Sequence (SECIS) element, which is critical for the production of selenoproteins.

Clinical and effectiveness evidence

Human studies and cell models demonstrate that the rs713041 genotype shifts the "saturation point" for selenium-dependent antioxidant defenses.

• Genotype-Specific Requirements: Individuals with the TT genotype may require higher serum selenium levels—estimated between 116–149 ng/mL—to reach optimal antioxidant enzyme activity compared to those with the C variant.
• Differential Response to Intake: In supplementation trials (using high-selenium sources like Brazil nuts), the GPX4 genotype influenced the response of other selenoproteins, such as erythrocyte GPx1 and plasma GPx3. This indicates that the rs713041 variant acts as a "master switch" that modulates the wider selenoproteome response to dietary intake.
• Health Correlations: Because of this differential response, the T variant has been associated with an increased risk for conditions linked to oxidative stress, including colorectal cancer, vascular disease, and severe outcomes in viral infections like COVID-19, particularly when selenium status is suboptimal.

Mechanistic explanations

The mechanism is driven by the structural integrity of the SECIS element, which is essential for translating the UGA stop codon into the amino acid selenocysteine.

• Binding Affinity: The T allele alters the stem-loop structure of the SECIS element, which impairs the binding of SECIS-binding protein 2 (SBP2). This reduces the efficiency of GPX4 synthesis.
• Selenoprotein Hierarchy: Selenoproteins are produced according to a strict hierarchy when selenium is limited. The C/T polymorphism alters this hierarchy. Under low selenium conditions, the T variant appears to compete differently for available selenium than the C variant.
• High Selenium Sensitivity: When selenium levels are high, the C variant (wild-type) demonstrates a significantly more robust increase in GPX4 expression and antioxidant protection. In contrast, the T variant's less efficient SECIS structure may limit its ability to scale antioxidant production as effectively, potentially leaving the cellular redox balance more sensitive to fluctuations in selenium availability.

Bottom line

The GPX4 rs713041 genotype dictates how efficiently selenium intake is converted into antioxidant protection. Carriers of the T variant may have a higher threshold for selenium "sufficiency" and a different redox sensitivity profile compared to C carriers, necessitating a more personalized approach to selenium supplementation.