What you carry at this position in your DNA and what research says about it.
Antioxidant Enzyme Activity: 8/10 evidence, 29 publications.
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Sample genotype (not yours): C/C
Typical Antioxidant Levels and Baseline Health Risks
Baseline levels of the catalase enzyme provide standard protection against oxidative stress. Standard risks are observed for respiratory infections and cellular defense.
What this genotype means: Standard cellular antioxidant capacity; Typical baseline risk for respiratory infections.
Sample genotype (not yours): C/T
Higher Antioxidant Levels but Increased COVID-19 Risk
Enhanced catalase production offers stronger protection against oxidative stress and lower tumor risks. However, this altered cellular environment is linked to higher risks of severe viral infections.
What this genotype means: Increased antioxidant enzyme levels; Lower acoustic neuroma risk; Higher risk of severe COVID-19 response.
Sample genotype (not yours): T/T
Elevated Antioxidant Levels but Higher COVID-19 Risk
Maximum catalase expression provides superior defense against oxidative damage and lowers certain tumor risks. This cellular shift simultaneously increases the likelihood of severe respiratory complications.
What this genotype means: Highest antioxidant enzyme levels; Significantly lower acoustic neuroma risk; Higher risk of severe COVID-19 response.
Gene function and biological role
Gene Function: The CAT gene provides instructions for producing catalase, one of the body's most critical antioxidant enzymes [1]. Catalase is responsible for rapidly breaking down hydrogen peroxide, a potentially harmful reactive oxygen species, into harmless water and oxygen [1]. By neutralizing these free radicals, catalase plays a vital role in protecting cells throughout the body from oxidative stress and subsequent DNA damage [2]. This defense mechanism is especially active in the liver, kidneys, and red blood cells, where metabolic waste products frequently accumulate [1]. Variations in this gene can alter how much catalase is produced, directly influencing the body's systemic antioxidant capacity and susceptibility to oxidative damage [3].
Variant Impact: Located in the promoter region of the CAT gene, the rs1001179 variant modifies the rate at which the catalase enzyme is produced [3]. This specific change, often referred to as -262C>T, alters the binding sites for key transcription factors that control gene expression [3]. The presence of the thymine (T) allele generally leads to higher expression of catalase in blood cells and other tissues [1]. Consequently, this genetic shift enhances the body's baseline antioxidant defense system by accelerating the clearance of cellular hydrogen peroxide [3]. However, this alteration in cellular redox balance also influences susceptibility to certain inflammatory and infectious conditions [4].
Key Insight: The same genetic variant that boosts your cellular antioxidant defense and lowers certain tumor risks also increases your susceptibility to severe respiratory infections.
Location: CAT. Chromosome 11 · 11p13 · 34.4 Mb
Estimated prevalence by population
Global 70.9%; European 60.3%; African 90.9%; East Asian 93.4%; South Asian 60.0%; Americas 75.3%; Ashkenazi 60.3%; Finnish 53.0%; Middle Eastern 65.5%; Amish 51.6%.
Estimated CC genotype frequency.
Global 25.8%; European 34.7%; African 8.8%; East Asian 6.5%; South Asian 34.9%; Americas 22.9%; Ashkenazi 34.7%; Finnish 39.6%; Middle Eastern 30.8%; Amish 40.5%.
Estimated CT genotype frequency.
Global 3.4%; European 5.0%; African 0.2%; East Asian 0.1%; South Asian 5.1%; Americas 1.7%; Ashkenazi 5.0%; Finnish 7.4%; Middle Eastern 3.6%; Amish 7.9%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Nutrition & Metabolism
Blood Chemistry & Metabolites
Antioxidant Levels. Evidence: 8/10. Source: PMID 34648354. Typical.
Cancer & Oncology
Brain & Nervous System Cancers
Acoustic Neuroma. Evidence: 3/10. Source: PMID 21795425. Typical.
Immunity & Inflammation
Infection Susceptibility & Resistance
COVID-19 Severity. Evidence: 3/10. Source: PMID 39361370. Typical.
Cardiovascular & Metabolic
Diabetes & Glycemic Traits
Type 2 Diabetes. Evidence: 4/10. Source: PMID 35893037. Typical.
Pharmacogenomics
Chemotherapy Response
Hydroxyurea Response. Evidence: 5/10. Source: PMID 33013391. Typical.
Showing effects for C/T genotype
Antioxidant Levels. Evidence: 8/10. Source: PMID 34648354. Higher.
Acoustic Neuroma. Evidence: 3/10. Source: PMID 21795425. ~40% Lower Risk.
COVID-19 Severity. Evidence: 3/10. Source: PMID 39361370. Increased Risk.
Type 2 Diabetes. Evidence: 4/10. Source: PMID 35893037. Associated.
Hydroxyurea Response. Evidence: 5/10. Source: PMID 33013391. Stronger Response.
Showing effects for T/T genotype
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Standard cellular defense is maintained by typical levels of the catalase enzyme [1]. Having the common cytosine (C) allele on both chromosomes represents the baseline genetic profile for most populations worldwide [2]. While this profile does not offer the elevated antioxidant capacity associated with the variant allele, it also avoids the increased susceptibility to severe viral responses seen in carriers [3]. Research indicates typical baseline risks for conditions related to oxidative stress, such as metabolic changes and cellular damage [4]. Typical responses are also expected during therapies like hydroxyurea treatment for blood disorders [5]. This baseline state means the body relies heavily on standard lifestyle factors to manage daily oxidative loads [6]. Regular physical activity and a balanced diet are excellent ways to optimize this natural defense system [6].
Standard cellular antioxidant capacity; Typical baseline risk for respiratory infections.
Sample genotype: CT (Heterozygous)
Elevated catalase expression in blood cells provides a robust defense against harmful free radicals [1]. This genetic profile is associated with a significant reduction in the risk of developing acoustic neuroma, a benign brain tumor [2]. Furthermore, individuals with this profile show an improved therapeutic response to hydroxyurea, a common medication for sickle cell anemia [3]. However, the altered cellular environment also correlates with an increased risk of severe COVID-19 hospitalization [4]. Such a dual effect highlights how changes in cellular redox balance can be highly beneficial in some contexts while presenting challenges in others [1]. Because the T allele is relatively common, many people carry this balanced mix of traits. Focusing on cardiovascular health and respiratory wellness is a practical way to navigate these genetic tendencies [5].
Increased antioxidant enzyme levels; Lower acoustic neuroma risk; Higher risk of severe COVID-19 response.
Sample genotype: TT (Homozygous)
Peak catalase enzyme production significantly enhances the body's ability to neutralize hydrogen peroxide [1]. This homozygous variant genotype is linked to a notable forty percent reduction in the risk of acoustic neuroma [2]. Additionally, clinical studies show a significantly better response to hydroxyurea therapy, making it highly relevant for specific blood treatments [3]. Despite these clear advantages, the altered cellular state is strongly associated with higher rates of hospitalization during COVID-19 infections [4]. The increased catalase levels may modify immune signaling pathways during acute inflammatory responses [4]. Two copies of the T allele are less common, occurring in about three to twenty-eight percent of people depending on ancestry. Understanding these unique cellular dynamics allows for highly personalized wellness choices [5].
Highest antioxidant enzyme levels; Significantly lower acoustic neuroma risk; Higher risk of severe COVID-19 response.
Variants with shared genetic architecture
rs7943316 · CAT Gene · Chr 11 · Oxidative Stress Risk
rs1077989 · GPHN Gene · Chr 14 · Plasmalogen Lipid Levels
rs4673 · CYBA Gene · Chr 16 · Heart Disease Risk
Mapping the proteo-genomic convergence of human diseases.
Novel risk loci for COVID-19 hospitalization among admixed American populations.
Impact of oxidative stress SNPs and dietary antioxidant quality score on prostate cancer.
Content updated August 2026.
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