NAT2 rs1799930: Understanding Your Acetylation Status
The rs1799930 variant is a specific genetic change in the NAT2 gene that helps define an individual's ability to metabolize certain drugs. It is a primary marker used to categorize people into different 'acetylator' phenotypes, which can influence how the body processes medications such as isoniazid.
What each genotype means
Rapid or intermediate acetylator
This genotype contains the reference G allele, which is associated with normal or higher NAT2 enzyme activity. Individuals with this profile typically metabolize drugs like isoniazid more efficiently than those carrying the A allele. Please discuss your medication dosing and potential for drug-response variability with your clinician or pharmacist.
This genotype is common in many global populations, though its frequency varies significantly depending on ancestral background.
Intermediate acetylator
This genotype includes one copy of the A allele, which is part of the NAT2*6A haplotype associated with reduced enzyme function. You may metabolize certain medications at a moderate rate compared to individuals with two reference alleles. Please consult your healthcare provider or pharmacist regarding how this may influence your response to specific prescribed treatments.
This heterozygous genotype is frequently observed in European and South Asian cohorts, often appearing in a significant portion of the population.
Slow acetylator
This genotype consists of two copies of the A allele, which is linked to the NAT2*6A variant and reduced N-acetyltransferase 2 enzyme activity. Research indicates that individuals with this profile may be at an increased risk for drug-induced hepatotoxicity when taking medications like isoniazid. Always discuss your specific genotype and medication management with your clinician or pharmacist.
This homozygous genotype is found in a substantial percentage of individuals globally, with prevalence rates varying widely across different ethnic and geographic groups.
What is the rs1799930 Variant?
The rs1799930 variant is a single nucleotide polymorphism (SNP) located within the NAT2 gene. In scientific literature, this specific change is often referred to as a 590G>A missense mutation. This means that at a specific position in the DNA sequence, a guanine (G) is replaced by an adenine (A). This change is a defining component of the NAT2*6A haplotype. Because the NAT2 gene is highly polymorphic, meaning it has many variations, this SNP is one of several markers researchers use to determine how efficiently a person's enzymes can process, or 'acetylate,' specific chemical compounds. By identifying the presence of this variant, scientists can better understand the functional capacity of the NAT2 enzyme in an individual.
The Role of the NAT2 Gene
The NAT2 gene encodes the enzyme N-acetyltransferase 2. This enzyme plays a critical role in phase II metabolism, a process where the body modifies drugs and other foreign substances to make them easier to eliminate. NAT2 is responsible for the acetylation of various arylamine and hydrazine drugs, including the tuberculosis medication isoniazid and the anti-inflammatory drug sulfasalazine. Because the NAT2 gene is highly variable, human populations are often categorized into three distinct phenotypes: rapid, intermediate, and slow acetylators. These categories describe how quickly an individual's body clears these specific drugs from their system. Variations like rs1799930 are associated with reduced enzyme function, which can shift an individual toward a 'slow acetylator' status, potentially leading to higher concentrations of certain drugs in the bloodstream.
Research and Clinical Associations
Research into rs1799930 primarily focuses on pharmacogenomics, the study of how genes affect drug response. The evidence linking this variant to drug metabolism is well-established in the context of isoniazid-induced liver injury. Because slow acetylators clear isoniazid more slowly, they may be at a higher risk for adverse reactions if the drug accumulates. However, it is important to note that the evidence strength for clinical outcomes can be limited by other factors, such as diet, environmental exposures, and the presence of other genetic variants. While the association between NAT2 genotype and drug clearance is strong, the clinical manifestation of side effects is complex and not determined by this single SNP alone. Always consult with your physician or pharmacist before making any decisions regarding your medication based on genetic information.
Population Frequency
The rs1799930 variant is relatively common, with a minor allele frequency typically reported between 20% and 30% in European and South Asian populations. Because NAT2 is highly diverse, the frequency of this variant and the resulting acetylator phenotypes vary significantly across different global ancestries.
What You Can Do With This Information
Understanding your NAT2 genotype can provide context for how your body might process specific medications, but it should never be used for self-diagnosis or to alter your medical treatment. Genetic testing results are only one piece of a much larger clinical puzzle. If you have received genetic testing results that mention the rs1799930 variant, the most important step is to discuss these findings with your healthcare provider or a clinical pharmacist. They can interpret these results in the context of your overall health, current medications, and medical history. Never stop or change the dosage of a prescribed medication based on genetic data without professional medical guidance. Your clinician can determine if your specific genotype warrants a change in therapy or closer monitoring for potential side effects.
How common is this variant?
The rs1799930 variant is common, with a minor allele frequency of approximately 20-30% in European and South Asian cohorts.
Frequently asked questions
What does it mean to be a 'slow acetylator'?
Being a slow acetylator means your body processes certain drugs more slowly than average because your NAT2 enzyme activity is reduced. This can lead to higher levels of the drug in your blood, which may increase the risk of side effects.
Does having the rs1799930 variant mean I will have a drug reaction?
No, having this variant does not guarantee you will have a drug reaction. It is only one factor that influences how your body handles medication, and many other variables, including your overall health and other medications, play a role.
Should I get tested for NAT2 variants?
Genetic testing for NAT2 is generally not performed unless it is clinically relevant to a specific medication you are being prescribed. You should discuss the necessity of such testing with your doctor.
Can I change my acetylator status?
No, your acetylator status is determined by your genetics and cannot be changed. However, knowing your status can help your doctor choose the most appropriate medication and dosage for you.
Sources & further reading
Educational information only, last refreshed 9/29/2026. 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.
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.
Tag SNP defining the rapid versus slow N-acetyltransferase 2 acetylator phenotype, showing substantial allele frequency divergence across world ancestries.