PON1 rs662: Understanding the Q192R Genetic Variant
The rs662 variant, commonly known as the Q192R substitution, occurs in the PON1 gene, which encodes an enzyme involved in protecting lipids from oxidation. Research investigates how this variant influences the enzyme's catalytic efficiency and its potential association with cardiovascular health.
What each genotype means
High antioxidant protection
This genotype encodes the glutamine (Q) variant at position 192 of the PON1 enzyme. Research suggests this form may offer greater protection against LDL oxidation compared to the arginine (R) variant. While some studies associate this with a lower risk of certain cardiovascular conditions, the overall clinical impact remains a subject of ongoing scientific investigation.
Carried by approximately 40-50% of individuals in many European populations, though frequencies vary significantly by ancestry.
Intermediate enzyme activity
This genotype represents a heterozygous state, carrying one copy of the glutamine (Q) allele and one copy of the arginine (R) allele. Individuals with this profile typically exhibit intermediate PON1 enzyme activity levels. The functional consequences of this mix are complex and may depend on other genetic and environmental factors.
This is a common genotype found in a significant portion of the global population, often appearing in roughly 40-50% of individuals in European-derived groups.
Reduced antioxidant efficiency
This genotype encodes the arginine (R) variant at position 192 of the PON1 enzyme. Some research indicates this form is less effective at inhibiting LDL oxidation and may be associated with an increased risk of certain cardiovascular diseases in specific populations. If you have concerns regarding your cardiovascular health or metabolic profile, please discuss these findings with your clinician.
Carried by roughly 1 in 10 to 1 in 5 people of European ancestry, but is significantly more common in East Asian populations, where it may be found in over 60% of individuals.
What is the rs662 Variant?
The rs662 variant is a single-nucleotide polymorphism (SNP) located within the PON1 gene on chromosome 7. This specific change results in an amino acid substitution at position 192 of the paraoxonase 1 protein, where glutamine (Q) is replaced by arginine (R). Because this position is located within the enzyme's active site, the substitution can alter how the protein interacts with various substrates. In genetic databases, the 'A' allele corresponds to the glutamine (Q) form, while the 'G' allele corresponds to the arginine (R) form. This variant is widely studied because the PON1 enzyme plays a significant role in the body's defense against oxidative stress, particularly by helping to prevent the oxidation of low-density lipoprotein (LDL) cholesterol, which is a key factor in cardiovascular health.
The Role of the PON1 Gene
The PON1 gene provides instructions for making the paraoxonase 1 enzyme, which is primarily synthesized in the liver and circulates in the blood attached to high-density lipoprotein (HDL) particles. This enzyme acts as an esterase, meaning it has the ability to break down certain chemical bonds. Beyond its role in lipid metabolism, PON1 is known for its capacity to hydrolyze organophosphates, which are compounds found in some pesticides and nerve agents. By protecting HDL and LDL particles from oxidative damage, the enzyme is thought to contribute to the body's overall antioxidant defense system. Variations in the gene, such as rs662, can change the enzyme's catalytic efficiency, meaning different individuals may process specific substrates at different rates depending on their inherited genotype.
Research and Clinical Associations
Scientific research into rs662 has produced mixed and sometimes conflicting results regarding its impact on human health. Many studies have explored whether the R allele is associated with an increased risk of coronary artery disease or other cardiovascular conditions, but findings vary significantly across different populations. Some studies suggest that the Q isoform may be more effective at preventing LDL oxidation, while others have found no clear link between the genotype and clinical outcomes. Additionally, the variant has been investigated for its role in organophosphate toxicity, with evidence suggesting that genetic differences might influence how individuals metabolize these substances. Because the evidence is often limited or ancestry-specific, it is important to view these associations as statistical observations rather than definitive predictors of individual health outcomes.
Population Frequency
The frequency of the rs662 alleles varies considerably across global populations. In many European populations, the Arg (G) allele frequency is approximately 0.30, while in East Asian populations, it is often observed at frequencies greater than 0.60. These differences highlight the importance of considering ancestral background when interpreting genetic data, as the prevalence of specific genotypes is not uniform worldwide.
What This Information Means for You
Understanding your genotype for rs662 provides insight into your genetic makeup, but it does not serve as a medical diagnosis. Because the scientific evidence regarding the health implications of this variant is complex and often inconclusive, it should not be used to make personal health decisions or lifestyle changes. If you are concerned about cardiovascular health, lipid profiles, or potential sensitivities to medications or environmental chemicals, the most appropriate step is to consult with a qualified healthcare professional. They can provide context based on your full medical history, clinical blood work, and other relevant factors. If you are interested in how this variant might affect your response to specific medications, please discuss this with your clinician or pharmacist, who can provide guidance based on established pharmacogenetic guidelines.
How common is this variant?
The Arg (G) allele frequency is approximately 0.30 in European populations and exceeds 0.60 in East Asian populations.
Frequently asked questions
Is the PON1 rs662 variant a cause of heart disease?
The rs662 variant is associated with cardiovascular risk in some studies, but the evidence is inconsistent and often varies by population. It is considered a potential risk factor rather than a direct cause of heart disease.
Does my rs662 genotype affect how I process medications?
PON1 is involved in the metabolism of certain substances, including some drugs. If you are concerned about how your genetics might influence your response to a specific medication, please discuss this with your doctor or pharmacist.
Can I change my PON1 activity levels?
While your genotype is fixed, PON1 activity can be influenced by various environmental and lifestyle factors. Consult a healthcare provider for advice on maintaining heart health through diet and exercise.
Should I get tested for the rs662 variant?
Genetic testing for this variant is not currently recommended for routine clinical care. Because the clinical significance is not fully established, testing is generally not useful for making personal health decisions.
Sources & further reading
Educational information only, last refreshed 9/27/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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