NQO1 rs1800532: Understanding the Pro187Ser Genetic Variant
The rs1800532 variant in the NQO1 gene, often referred to as Pro187Ser, results in a protein with significantly reduced enzymatic activity. This variant is studied for its potential role in how the body processes certain toxins and its association with individual susceptibility to various health conditions.
What each genotype means
Normal enzyme activity
This genotype represents the wild-type form of the NQO1 gene, which typically produces a fully functional enzyme. This enzyme helps protect cells by detoxifying certain compounds, though research on its specific role in cancer susceptibility remains inconsistent and controversial. If you are concerned about how this variant might influence your response to specific medications, please discuss this with your clinician or pharmacist.
This is the most common genotype in many populations, though frequencies vary significantly by ancestry.
Reduced enzyme activity
Carrying one copy of the T allele (also known as the Pro187Ser or NQO1*2 variant) is associated with reduced NQO1 enzyme activity compared to the CC genotype. While some studies have investigated whether this reduction influences cancer risk or drug metabolism, the findings are often mixed or inconclusive. Please consult with your healthcare provider or pharmacist regarding any potential implications for your health or medication management.
This genotype is found in a significant portion of the population, with frequencies varying by ethnic background.
Null enzyme activity
Individuals with this homozygous genotype have significantly reduced NQO1 enzyme activity, often reported as only 2-4% of normal levels. This variant, known as Pro187Ser or NQO1*2, has been studied for its potential impact on how the body processes certain toxins and chemotherapeutic agents. Because the clinical significance of this reduced activity is still being researched, you should discuss any specific health or medication concerns with your clinician or pharmacist.
This genotype is less common than the CC or CT genotypes, with prevalence rates that differ notably across various global populations.
What is the rs1800532 Variant?
The rs1800532 variant is a single nucleotide polymorphism (SNP) located within the NQO1 gene on chromosome 16. Specifically, it involves a change from a cytosine (C) to a thymine (T) at position 609 of the gene sequence. This specific change leads to an amino acid substitution where proline is replaced by serine at position 187 of the resulting protein, which is why it is frequently called the Pro187Ser polymorphism. Because this change occurs in the coding region of the gene, it directly alters the structure of the NQO1 enzyme. Research has consistently demonstrated that this structural change leads to a protein that is highly unstable and prone to rapid degradation within the cell, resulting in a dramatic loss of functional enzymatic activity compared to the common version of the protein.
The Role of the NQO1 Gene
The NQO1 gene encodes the enzyme NAD(P)H:quinone oxidoreductase 1. This enzyme plays a critical role in cellular defense by catalyzing the two-electron reduction of quinones and their derivatives into hydroquinones. By converting these reactive compounds into more stable, less toxic forms, the NQO1 enzyme helps protect cells against oxidative stress and potential DNA damage. Because it is involved in the detoxification of various xenobiotics—substances foreign to the body—it is a key player in pharmacogenomics. When the NQO1 enzyme is absent or non-functional, as is the case with the rs1800532 variant, the cell's ability to neutralize these reactive compounds is significantly impaired. This has led researchers to investigate whether individuals with this variant might have different responses to certain environmental toxins or specific chemotherapeutic agents that require activation or detoxification by this enzyme.
Research and Clinical Associations
The association between rs1800532 and health outcomes has been the subject of extensive research, particularly regarding cancer susceptibility. Because the variant leads to reduced detoxification capacity, scientists hypothesized that it might increase the risk of various cancers, including lung, bladder, and colorectal cancer. However, the evidence remains mixed and often controversial. While some studies suggest a correlation between the variant and altered cancer risk, others have found no significant link, or have noted that the effects are highly dependent on other factors like smoking status or ethnicity. Because the evidence is limited and inconsistent, it is not currently used as a definitive diagnostic tool. If you are concerned about how your genetic profile might influence your response to medications or your health risks, it is essential to discuss these findings with a qualified clinician or pharmacist who can interpret them in the context of your overall medical history.
Understanding Your Results
Genetic information regarding rs1800532 provides insight into your biological potential for enzyme activity, but it does not predict health outcomes with certainty. The presence of the T allele (the variant) does not mean you will develop a specific disease, nor does the presence of the C allele (the common form) guarantee protection. Many factors, including environment, lifestyle, and other genetic variations, contribute to your health. If you have received results indicating you carry the T allele, remember that this is a common variation found in many healthy individuals. This information is most useful when discussed with a healthcare professional, especially if you are undergoing medical treatments that involve drugs metabolized by NQO1. Always consult with your doctor before making any changes to your health management plan based on genetic data, as they can provide the necessary context and clinical guidance.
How common is this variant?
The minor allele frequency for rs1800532 is approximately 0.15-0.25 in European populations and significantly higher, ranging from 0.40-0.50, in East Asian populations.
Frequently asked questions
What does the NQO1 rs1800532 variant do?
The rs1800532 variant causes the NQO1 enzyme to be unstable and lose most of its functional activity. This enzyme is responsible for detoxifying certain harmful compounds in the body.
Does having the TT genotype mean I will get cancer?
No, having the TT genotype does not mean you will develop cancer. While some studies have explored links between this variant and cancer risk, the results are inconsistent and influenced by many other factors.
Should I change my medication if I have this variant?
You should never change your medication based on genetic results without consulting your doctor. Please discuss your genetic profile with your clinician or pharmacist to determine if it is relevant to your specific treatment.
Is this variant common?
Yes, this variant is relatively common, though its frequency varies significantly by ancestry. It is found more frequently in East Asian populations compared to European populations.
Sources & further reading
Educational information only, last refreshed 9/21/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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