ABCG2 rs77542162: Understanding This Pharmacogenomic Variant
The rs77542162 variant is a specific genetic change located within the ABCG2 gene. It is associated with a premature stop codon that may result in non-functional transporter activity, potentially influencing how the body processes certain medications like rosuvastatin.
What each genotype means
Typical transporter activity
This genotype represents the most common form of the ABCG2 gene in most populations. Individuals with this profile are expected to have standard BCRP transporter function, which helps regulate the plasma concentration of medications like rosuvastatin. Please discuss any medication dosing or concerns with your clinician or pharmacist.
This is the most common genotype globally, though its prevalence varies significantly by ancestry.
Reduced transporter activity
This genotype includes one copy of the variant associated with a premature stop codon (p.Gln126Ter), which may lead to reduced or non-functional BCRP transporter activity. Research suggests this can result in higher plasma concentrations of certain medications, such as rosuvastatin, compared to those without the variant. Please discuss your medication management and potential dosing adjustments with your clinician or pharmacist.
This genotype is observed with a minor allele frequency of approximately 1-3% in East Asian populations and is considered rare in other populations.
Significantly reduced transporter activity
This genotype includes two copies of the variant associated with a premature stop codon (p.Gln126Ter), which is expected to result in significantly reduced or absent BCRP transporter activity. This may lead to notably higher plasma concentrations of medications like rosuvastatin, potentially increasing the risk of side effects. Please consult your clinician or pharmacist to discuss how this genotype may influence your specific medication therapy.
This genotype is very rare, occurring primarily in East Asian populations at a low frequency.
What is the rs77542162 Variant?
The rs77542162 variant is a single nucleotide polymorphism (SNP) found within the ABCG2 gene. In genetic terms, this specific variant is characterized as a premature stop codon polymorphism, often referred to as p.Gln126Ter. A stop codon acts as a signal for the cellular machinery to cease the production of a protein prematurely. Because this variant interrupts the normal sequence of the ABCG2 gene, it can lead to the production of a truncated, non-functional protein. This is significant because the ABCG2 gene is responsible for creating the BCRP (Breast Cancer Resistance Protein) transporter, which plays a critical role in moving various substances, including medications, across cell membranes. When this transporter is non-functional, it can alter the concentration of these substances in the bloodstream.
The Role of the ABCG2 Gene
The ABCG2 gene provides instructions for making a protein that functions as an ATP-binding cassette transporter. These transporters are essentially molecular pumps that move molecules out of cells. The BCRP transporter, encoded by ABCG2, is expressed in various tissues, including the liver, intestines, and kidneys. Its primary job is to facilitate the excretion of toxins, metabolic waste products, and certain drugs from the body. By pumping these substances into bile or urine, the BCRP transporter helps regulate the levels of these compounds in the blood. When the gene is functioning normally, it helps maintain homeostasis. However, when variants like rs77542162 disrupt this process, the body's ability to clear specific drugs or compounds is impaired, which can lead to higher-than-expected levels of those substances in the plasma.
Research and Pharmacogenomic Associations
Research into ABCG2 has highlighted its importance in pharmacogenomics, particularly regarding the metabolism of statins like rosuvastatin. Studies suggest that individuals with reduced or non-functional ABCG2 activity may experience increased plasma concentrations of rosuvastatin. Higher concentrations of this medication in the blood are sometimes associated with an increased risk of statin-induced myotoxicity, or muscle-related side effects. While the evidence for rs77542162 specifically is considered limited compared to more common variants like Q141K, it is categorized as a variant of interest due to its potential to impact drug transport. It is important to note that drug response is often polygenic, meaning multiple genes and environmental factors contribute to how an individual reacts to a medication. Therefore, the presence of this variant alone does not guarantee a specific clinical outcome.
Population Frequency
The frequency of genetic variants can vary significantly across different ancestral groups. According to current data, the rs77542162 variant is relatively rare in the general population. It is observed with a minor allele frequency (MAF) of approximately 0.01 to 0.03 in East Asian populations, while it remains very rare or absent in many other global populations. This ancestral specificity is a common theme in pharmacogenomics, where certain variants are more prevalent in specific geographic regions. Understanding these frequency differences is essential for researchers and clinicians when evaluating the potential impact of a variant on a patient's health or medication response, as it helps contextualize the likelihood of an individual carrying the variant.
Managing Your Genetic Information
If you have information about your genotype for rs77542162, it is important to approach it with the right perspective. This information is intended for educational purposes and should not be used to make personal medical decisions, such as starting, stopping, or changing the dosage of any medication. Genetic variants are only one piece of a much larger puzzle that includes your overall health, other medications you may be taking, and your lifestyle. If you are concerned about how your genetics might influence your response to a medication like rosuvastatin, the best course of action is to discuss this with your healthcare provider or a clinical pharmacist. They can interpret your results in the context of your full medical history and provide guidance tailored to your specific needs.
How common is this variant?
The rs77542162 variant has a minor allele frequency of approximately 0.01-0.03 in East Asian populations and is considered rare in other populations.
Frequently asked questions
What does it mean if I have the rs77542162 variant?
Having this variant means you carry a genetic change that may affect the function of the BCRP transporter. This could potentially influence how your body processes certain medications, but it does not mean you will definitely experience side effects.
Should I change my medication if I have this variant?
No. You should never change your medication or dosage based on genetic information without consulting your doctor. Your clinician will consider your genetic results alongside other factors to determine the safest treatment plan for you.
Is rs77542162 the same as the common ABCG2 Q141K variant?
No, they are different variants within the same gene. While both are involved in ABCG2 function, they are distinct genetic changes with different frequencies and research histories.
Where can I find more information about pharmacogenomics?
You can visit resources like PharmGKB or MedlinePlus Genetics for reliable, evidence-based information on how genes affect drug response. These sites provide comprehensive overviews of the field.
Sources & further reading
Educational information only, last refreshed 10/16/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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