NAT2 rs1495741: What Your Genotype Means
The rs1495741 variant is a genetic marker located near the NAT2 gene, which is responsible for producing an enzyme that processes various drugs and chemicals. This SNP is often used as a 'tag' to help predict whether an individual is a rapid, intermediate, or slow acetylator, a trait that influences how the body metabolizes certain medications.
What each genotype means
Slow N-acetyltransferase 2 activity
This genotype is associated with a slow acetylator phenotype, meaning your body may process certain medications and environmental compounds more slowly than others. This can influence how you respond to drugs like isoniazid or hydralazine, potentially affecting the risk of side effects. Please discuss your medication dosing and any concerns with your clinician or pharmacist.
The frequency of this genotype varies significantly by ancestry, being common in many global populations.
Intermediate N-acetyltransferase 2 activity
This genotype is associated with an intermediate acetylator phenotype, suggesting your body processes certain medications at a rate between slow and rapid metabolizers. This status may influence your response to specific drugs metabolized by the NAT2 enzyme. Please discuss your medication dosing and any concerns with your clinician or pharmacist.
This heterozygous genotype is frequently observed across diverse global populations.
Rapid N-acetyltransferase 2 activity
This genotype is associated with a rapid acetylator phenotype, meaning your body may process certain medications and compounds more quickly than others. This can influence the effectiveness or required dosage of drugs metabolized by the NAT2 enzyme. Please discuss your medication dosing and any concerns with your clinician or pharmacist.
The frequency of this genotype varies by ancestry, with notable differences observed between East Asian, European, and African populations.
Understanding the rs1495741 Variant
The rs1495741 variant is a single nucleotide polymorphism (SNP) situated approximately 14,000 base pairs downstream from the NAT2 gene on chromosome 8. In genetic research, this SNP is frequently utilized as a 'tag' because it serves as a proxy for the complex patterns of variation found within the NAT2 gene itself. Rather than sequencing the entire gene, researchers have historically used this single marker to estimate an individual's acetylation status. While it has shown high predictive accuracy in populations of European ancestry, its reliability can vary across different global populations due to the unique genetic architecture of the NAT2 region. It is important to note that while this SNP is a useful tool for molecular epidemiology, it is an indirect marker rather than the functional cause of the enzyme's activity levels.
The Role of the NAT2 Gene
The NAT2 gene encodes the N-acetyltransferase 2 enzyme, which is primarily active in the liver and intestines. This enzyme plays a critical role in Phase II metabolism, a process where the body chemically modifies substances to make them easier to excrete. NAT2 is responsible for the acetylation of various xenobiotics, including certain drugs and environmental toxins. The efficiency of this enzyme varies significantly between individuals, leading to distinct 'acetylator phenotypes.' People are generally categorized as rapid, intermediate, or slow acetylators based on how quickly their NAT2 enzyme processes these compounds. This variation is clinically significant because it can influence the effectiveness of medications, such as the tuberculosis drug isoniazid, and may affect an individual's susceptibility to certain adverse drug reactions or toxicities.
Research and Evidence Strength
The association between rs1495741 and the NAT2 phenotype is well-documented in scientific literature, particularly as a tool for population-level studies. Research has demonstrated that the genotypes at this position correlate with the conventional NAT2 alleles that determine enzyme activity. However, the evidence strength for using this single SNP as a definitive clinical diagnostic tool is considered limited. Studies have shown that while rs1495741 performs well in some groups, other combinations of SNPs—such as a two-SNP panel or the traditional seven-SNP panel—often provide higher accuracy in predicting an individual's true metabolic phenotype. Because of this, clinicians typically rely on more comprehensive genotyping methods when making specific medical decisions. The scientific community continues to evaluate how ancestry-specific genetic diversity impacts the predictive power of this tag SNP.
Population Frequency and Diversity
The distribution of the rs1495741 variant shows substantial divergence across different world ancestries, reflecting the complex evolutionary history of the NAT2 gene. Data from large-scale projects like the 1000 Genomes and gnomAD indicate that the minor allele frequency (MAF) for the A allele is approximately 0.26 in East Asian populations, 0.42 in African populations, and 0.50 in European populations. These differences mean that the prevalence of predicted rapid, intermediate, and slow acetylator phenotypes varies significantly depending on an individual's ancestral background. Because NAT2 genetic diversity is shaped by both balancing and directional selection, these frequency patterns are not uniform globally. Understanding these population-specific frequencies is essential for researchers conducting epidemiological studies, as it highlights why a single marker may not be equally predictive across all ethnic groups.
What This Information Means for You
If you have received information about your rs1495741 genotype, it is important to view it as a general indicator of your potential acetylation status rather than a medical diagnosis. This variant is a research tool used to estimate how your body might process certain substances, but it does not account for all the factors that influence drug metabolism, such as diet, environment, or other genetic variations. You should never use this information to make changes to your medication regimen or dosage. If you are concerned about how your body processes a specific drug, or if you are experiencing side effects, please discuss these findings with your clinician or a pharmacist. They can provide context based on your full medical history and, if necessary, recommend validated clinical testing to guide your treatment plan.
How common is this variant?
The A allele frequency is approximately 0.26 in East Asians, 0.42 in African populations, and 0.50 in European populations, showing significant ancestral variation.
Frequently asked questions
Can I use rs1495741 to predict my drug response?
While rs1495741 is a marker for NAT2 activity, it is not a substitute for clinical testing. It provides an estimate, but you should consult your doctor for personalized medical advice regarding drug response.
Is rs1495741 the same as a NAT2 test?
No, rs1495741 is a single tag SNP. A full clinical NAT2 test typically examines multiple specific variants to determine your exact acetylator status with higher accuracy.
What does it mean to be a slow acetylator?
A slow acetylator has a reduced capacity to process certain drugs via the NAT2 enzyme. This can lead to higher levels of the drug in the blood, which may increase the risk of side effects.
Does my ancestry affect my NAT2 genotype?
Yes, the frequency of NAT2 variants varies significantly across different global populations. This means the likelihood of having a specific genotype depends partly on your ancestral background.
Should I change my medication based on this SNP?
Absolutely not. Never change your medication or dosage based on genetic test results without speaking to your healthcare provider or pharmacist first.
Sources & further reading
Educational information only, last refreshed 9/26/2026. 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.