NAT2 rs1799931: What Your Genotype Means
The rs1799931 variant is a specific genetic change located within the NAT2 gene, which provides instructions for an enzyme that processes various drugs and chemicals. This variant is primarily studied in the field of pharmacogenomics because it is associated with a 'slow acetylator' phenotype, affecting how efficiently the body metabolizes certain medications.
What each genotype means
Normal enzyme activity
This genotype is associated with the rapid or normal acetylator phenotype for the NAT2 enzyme. Individuals with this genotype typically metabolize drugs like isoniazid at a standard rate, though overall acetylation status is determined by the combination of all NAT2 variants. Please discuss your medication dosing and potential side effects with your clinician or pharmacist.
This is the most common genotype in many global populations, though its frequency varies significantly by ancestry.
Reduced enzyme activity
This genotype includes one variant allele, which is associated with reduced NAT2 enzyme activity compared to the reference. You may be classified as an intermediate acetylator, which can influence how your body processes medications like isoniazid or hydralazine. Please consult your healthcare provider or pharmacist regarding personalized dosing strategies.
This genotype is found at moderate frequencies in many populations and is particularly notable in East Asian and Indigenous American ancestries.
Slow enzyme activity
This genotype is associated with the slow acetylator phenotype, as it carries two copies of the variant allele. Slow acetylators may clear certain drugs, such as isoniazid, more slowly, which can increase the risk of drug-induced side effects. Always inform your clinician of your genetic status when starting new medications to ensure appropriate dosing.
This genotype is observed in approximately 10-15% of individuals in East Asian and Indigenous American populations, but is significantly rarer in European ancestry groups.
Understanding the NAT2 Gene and rs1799931
The NAT2 gene encodes the N-acetyltransferase 2 enzyme, which is responsible for the phase II metabolism of many drugs and environmental toxins. The rs1799931 variant, also known as c.857G>A or p.Gly286Glu, is a single nucleotide polymorphism (SNP) where a guanine (G) is replaced by an adenine (A). This specific change is a defining marker for the NAT2*7 allele group. Because the NAT2 enzyme is critical for breaking down substances like isoniazid—a common treatment for tuberculosis—variations in this gene can significantly alter how quickly or slowly a person clears these drugs from their system. When the enzyme's function is reduced due to variants like rs1799931, individuals are often classified as 'slow acetylators,' which may influence both the therapeutic effectiveness and the potential side-effect profile of certain medications.
Research and Clinical Associations
Research into rs1799931 is largely focused on pharmacogenomics and cancer susceptibility. In clinical settings, the primary concern is the metabolism of drugs like isoniazid, where slow acetylators may be at a higher risk for drug-induced side effects because the medication remains in the body for a longer duration. Beyond pharmacology, some studies have investigated whether this variant influences cancer risk by altering how the body processes potential carcinogens, such as heterocyclic amines found in cooked foods. However, the evidence regarding cancer risk remains mixed and inconsistent across different populations. While some meta-analyses have suggested a potential protective effect of the A allele against certain cancers in specific groups, these findings are not definitive. Because the evidence strength for these associations is currently limited, this genetic information is generally used to support clinical decision-making regarding drug dosing rather than as a standalone diagnostic tool.
Population Frequency and Distribution
The frequency of the rs1799931 variant varies significantly across different global populations. It is notably more prevalent in East Asian and Indigenous American ancestries, where the A allele frequency can reach approximately 10-15%. In contrast, this variant is relatively rare in populations of European ancestry. Understanding these ancestral differences is crucial for researchers and clinicians, as it highlights why pharmacogenetic testing may have different clinical implications depending on a patient's background. Because NAT2 exhibits high levels of haplotype diversity, the presence of rs1799931 is often analyzed alongside other NAT2 SNPs to accurately predict an individual's overall acetylator status. The global landscape of this gene is complex, and the distribution of its variants reflects historical migration patterns and selective pressures that have shaped human genetic diversity over thousands of years.
What This Information Means for You
If you have received results regarding your NAT2 genotype, it is important to interpret them within the context of your overall health and any medications you may be taking. Genetic variants like rs1799931 provide a piece of the puzzle regarding how your body processes substances, but they do not act in isolation. Many factors, including age, liver function, diet, and other medications, also influence drug metabolism. You should never use genetic information to make changes to your prescribed medication regimen or to self-diagnose. If you are concerned about how your genetics might affect your response to a specific drug, the best course of action is to discuss your results with your physician or a clinical pharmacist. They can provide professional guidance on whether dose adjustments or alternative therapies are appropriate based on your specific genetic profile and clinical history.
How common is this variant?
The rs1799931 variant is particularly prevalent in East Asian and Indigenous American ancestries, occurring at frequencies of approximately 10-15%, while it remains rare in European populations.
Frequently asked questions
What does it mean to be a 'slow acetylator'?
A slow acetylator is someone whose body processes certain drugs more slowly than average because their NAT2 enzyme is less active. This can lead to higher levels of the drug in the blood, which might increase the risk of side effects.
Does rs1799931 cause cancer?
Current research on the link between rs1799931 and cancer is inconsistent and inconclusive. While some studies suggest it may influence how the body processes carcinogens, there is no definitive evidence that this variant directly causes cancer.
Should I change my medication based on my NAT2 results?
No, you should never change your medication based on genetic results without consulting your doctor. Only a healthcare professional can determine if your genetic profile requires a change in your treatment plan.
Is NAT2 testing standard for everyone?
NAT2 testing is not standard for the general population. It is typically considered in specific clinical scenarios, such as when a patient is starting a medication known to be metabolized by the NAT2 enzyme and the clinician needs to optimize the dosage.
Sources & further reading
Educational information only, last refreshed 9/20/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Coding variant c.481C>T (p.Leu161Leu) serving as a diagnostic marker for several NAT2 slow acetylator haplotypes, including *5.
Coding variant c.857G>A (p.Gly286Glu) defining the NAT2*14 allele (often associated with slow acetylation).
Synonymous variant (282C>T) associated with the NAT2*6 allele, contributing to slow acetylator status.
Missense variant (590G>A) defining the NAT2*6A allele, associated with slow acetylator phenotype.
Synonymous polymorphism (857G>A) representing the defining mutation of the slow acetylator NAT2*7 allele.
This variant (c.590G>A, p.Arg197Gln) is a well-characterized slow acetylator allele in the NAT2 gene, influencing the metabolism of drugs like isoniazid.