SLC22A1 rs62238264: Understanding Your Genetic Variant
The rs62238264 variant is a genetic change located within the SLC22A1 gene, which provides instructions for making a protein that transports drugs into cells. Research has investigated this variant for its potential association with how individuals respond to metformin, a common medication for type 2 diabetes.
What each genotype means
Typical SLC22A1 genotype
This genotype represents the most common form of the SLC22A1 gene at this location. Research into this specific intronic variant is limited, but it is generally considered the baseline against which potential differences in metformin response or tolerability are measured. Please discuss your medication response and any concerns about metformin therapy with your clinician or pharmacist.
This is the most frequent genotype in many populations, including those of European ancestry.
Heterozygous variant carrier
You carry one copy of the variant allele at this position in the SLC22A1 gene. Some studies suggest that variants in this gene may be associated with altered glycemic response or gastrointestinal tolerability to metformin, though evidence for this specific variant remains limited. You should consult your healthcare provider to monitor your response to metformin and discuss any side effects.
This genotype is common, appearing in approximately 30% to 35% of individuals in many European populations.
Homozygous variant carrier
You carry two copies of the variant allele at this position in the SLC22A1 gene. While this variant is located in a gene responsible for transporting metformin, the clinical impact of this specific intronic change is not fully established and remains a subject of ongoing research. Always work closely with your doctor or pharmacist to evaluate your personal response to metformin therapy.
This genotype is less common than the heterozygous form but is present in a significant portion of the population, particularly in European cohorts.
What is the rs62238264 Variant?
The rs62238264 variant is a specific change in the DNA sequence located within the SLC22A1 gene. In genetics, a single nucleotide polymorphism, or SNP, represents a variation at a single position in the DNA code. This particular variant is situated in an intronic region of the gene. Introns are segments of DNA that do not code for the final protein product but can play critical roles in regulating how genes are expressed or processed. Because rs62238264 is located in this regulatory-adjacent space, researchers study it to determine if it influences the amount or function of the transporter protein produced by the SLC22A1 gene. Understanding these small variations is a core component of pharmacogenomics, the study of how an individual's genetic makeup affects their response to medications.
The Role of the SLC22A1 Gene
The SLC22A1 gene encodes a protein known as the organic cation transporter 1, or OCT1. This protein acts like a gatekeeper on the surface of cells, particularly in the liver, where it helps move various substances, including medications, into the cell. By facilitating the entry of drugs into target tissues, OCT1 is essential for the proper distribution and action of many therapeutic agents. Metformin, a widely prescribed drug for managing blood glucose levels in type 2 diabetes, relies on transporters like OCT1 to enter liver cells, where it exerts its primary glucose-lowering effects. When the function of the OCT1 protein is altered due to genetic variation, it may theoretically change how much metformin reaches its target, potentially influencing the drug's efficacy or the patient's experience with the medication.
Research and Evidence Strength
Scientific research into rs62238264 has primarily focused on its potential link to metformin response in patients with type 2 diabetes. While some studies have explored whether this variant correlates with glycemic control or tolerability, the current evidence is considered limited. Pharmacogenomic associations are often complex, as drug response is influenced by a combination of multiple genes, environmental factors, diet, and lifestyle. While some published research suggests that variations in SLC22A1 can impact metformin pharmacokinetics, it is important to note that findings for specific intronic variants like rs62238264 are not always consistent across different study populations. Consequently, this variant is not currently used as a standard clinical tool for predicting how a patient will respond to metformin. Further large-scale, peer-reviewed studies are required to clarify the clinical significance of this specific SNP.
Population Frequency
Genetic variants are distributed differently across global populations, and rs62238264 is no exception. Current data indicates that this variant is relatively common in European populations, with a minor allele frequency estimated between 30% and 35%. This means that a significant portion of individuals of European descent carry at least one copy of the variant allele. Because frequency can vary significantly based on ancestral background, it is essential to consider population-specific data when interpreting genetic information. The prevalence of this variant highlights that many common genetic changes are widely shared within specific groups, yet their functional impact remains a subject of ongoing scientific investigation.
What This Information Means for You
It is important to understand that having a specific genotype for rs62238264 does not provide a definitive prediction of how you will respond to any medication. Pharmacogenomics is an evolving field, and genetic testing for this variant is not a standard part of clinical practice for metformin therapy. You should never use genetic information to make decisions about your health, such as stopping or changing the dosage of a prescribed medication. If you are curious about how your genetics might influence your treatment, the best course of action is to have a conversation with your healthcare provider or a clinical pharmacist. They can provide context based on your full medical history, current medications, and established clinical guidelines, ensuring that your treatment plan is safe and effective for your individual needs.
How common is this variant?
The rs62238264 variant is common in European populations, with a minor allele frequency of approximately 30% to 35%.
Frequently asked questions
Can I use this test to see if metformin will work for me?
No. Current clinical guidelines do not recommend using this genetic variant to guide metformin therapy. Drug response is complex and depends on many factors beyond a single genetic marker.
Should I change my medication if I have the 'risk' genotype?
Absolutely not. Never change your medication dosage or stop taking a prescribed drug without consulting your doctor. Genetic results are not a substitute for professional medical advice.
Is this variant the same as the *1 or *17 alleles?
No. The *1 and *17 nomenclature typically refers to specific functional haplotypes of the SLC22A1 gene. This SNP is a single position variant and is not equivalent to those star-allele classifications.
Where can I find more information on pharmacogenomics?
You can visit resources like PharmGKB or MedlinePlus Genetics for reliable, evidence-based information on how genes affect drug response. These sites provide summaries of current scientific knowledge.
Sources & further reading
Educational information only, last refreshed 9/18/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Get my report — $29Related variants in SLC22A1
Functional non-synonymous variant (M420del) in the organic cation transporter OCT1, significantly impacting the hepatic uptake of various drugs including metformin.
An intronic variant in the organic cation transporter gene associated with altered metformin side-effect profiles.
A variant associated with the occurrence of gastrointestinal side effects in metformin users.
Variant in SLC22A1 (OCT1) associated with altered metformin transport and glycemic response.
Also known as OCT1 p.Met420del, this loss-of-function deletion diminishes hepatic uptake and glycemic response to metformin in patients with type 2 diabetes.
A missense variant in OCT1 that impairs organic cation cellular uptake, altering clinical responsiveness and gastrointestinal tolerance to metformin.