SLCO1B1 rs4149032: What Your Genotype Means
The rs4149032 variant is a genetic change located within the SLCO1B1 gene, which provides instructions for a protein that helps the liver process various medications. This variant has been studied for its potential influence on how the body handles certain drugs, particularly in specific ancestral populations.
What each genotype means
Normal transporter function
This genotype is considered the reference or normal-function type for this variant. Research indicates that individuals with this genotype typically have standard hepatic uptake of certain statin medications. Please discuss any medication dosing or concerns regarding muscle symptoms with your clinician or pharmacist.
This is the most common genotype in most global populations.
Decreased transporter function
This genotype is associated with reduced activity of the OATP1B1 transporter, which may lead to higher levels of certain statins in the blood. Some studies suggest this may increase the risk of statin-associated muscle symptoms, though the clinical impact can vary by specific medication and individual factors. Please discuss your medication plan and any muscle-related symptoms with your healthcare provider.
Carried by a significant portion of the population, with a minor allele frequency of approximately 0.08 to 0.12 in European and African populations.
Significantly reduced transporter function
This genotype is associated with a more pronounced reduction in OATP1B1 transporter activity compared to the T/T genotype. Research has linked this profile to an increased risk of statin-induced muscle toxicity, particularly with medications like simvastatin. You should consult your clinician or pharmacist to discuss whether your current statin therapy is appropriate or if dosage adjustments are recommended.
This is the least common genotype, occurring less frequently than the T/T and T/C genotypes in most studied populations.
Understanding the rs4149032 Variant
The rs4149032 variant is a single nucleotide polymorphism (SNP) located in the SLCO1B1 gene. In genetics, a SNP represents a variation at a single position in the DNA sequence. This specific variant is a non-synonymous coding polymorphism, meaning it results in an amino acid change (p.Asn130Asp) in the protein produced by the gene. This change defines the SLCO1B1*30 allele. Scientists study such variants to understand how minor differences in our genetic code can lead to variations in how individuals process medications. Because this variant is located in a gene responsible for transporting substances into the liver, researchers have investigated whether it alters the efficiency of drug uptake, which could theoretically impact the concentration of a drug in the bloodstream.
The Role of the SLCO1B1 Gene
The SLCO1B1 gene encodes the organic anion transporting polypeptide 1B1 (OATP1B1). This protein is primarily expressed in the liver, where it acts as a gatekeeper, facilitating the transport of various substances—including bile acids, hormones, and many prescription medications—from the blood into liver cells. Once inside the liver, these substances can be processed, metabolized, and eventually cleared from the body. When the function of the OATP1B1 protein is altered, it can change the rate at which these drugs are cleared. While the most well-known variants in this gene are associated with statin-induced muscle side effects, researchers continue to study other variants like rs4149032 to determine if they play a similar role in the pharmacokinetics of other therapeutic agents.
Research and Evidence Strength
The evidence linking rs4149032 to clinical outcomes is currently considered limited. While some studies have explored its impact, the findings are often specific to certain drugs or populations. For instance, research has examined the association between this variant and the metabolism of rifampin, an antibiotic used to treat tuberculosis, particularly in South African populations. In these studies, the T allele was associated with decreased rifampin exposure compared to the C allele. However, it is important to note that the clinical significance of these findings is still being evaluated. Unlike other well-established SLCO1B1 variants that have clear, actionable guidelines for statin dosing, the data for rs4149032 does not currently support widespread clinical testing or standardized dosing adjustments. Further research is required to confirm its role across different drug classes and diverse genetic backgrounds.
What This Information Means for You
If you have received information about your rs4149032 genotype, it is important to view it within the context of current scientific evidence. Because the evidence for this specific variant is limited and not currently used for routine clinical decision-making, it should not be used to make changes to your medication regimen. Genetic variants are only one of many factors—including age, diet, kidney function, and other medications—that influence how your body responds to drugs. If you are concerned about how a medication is affecting you, or if you are interested in 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 personalized guidance based on your full medical history and the most current clinical standards.
How common is this variant?
The rs4149032 variant is relatively common, with a minor allele frequency (MAF) typically ranging between 0.08 and 0.12 in both African and European populations.
Frequently asked questions
Is rs4149032 the same as the common statin-related SLCO1B1 variants?
No, rs4149032 is a different variant than the well-known SLCO1B1 variants (such as rs4149056) that are strongly associated with statin-induced myopathy. While they are in the same gene, they have different clinical implications and evidence levels.
Should I change my medication based on my rs4149032 result?
No, you should never change your medication based on a single genetic result. Always consult your doctor or pharmacist before making any changes to your prescribed treatment plan.
Why is the evidence for this variant considered limited?
Evidence is considered limited because there are few large-scale, replicated studies confirming a direct clinical impact on drug safety or efficacy. Most findings are preliminary or specific to certain drugs and populations.
Where can I find more information about my pharmacogenetic results?
You can discuss your results with a genetic counselor or a pharmacist who specializes in pharmacogenomics. They can help interpret your results in the context of your overall health.
Sources & further reading
Educational information only, last refreshed 10/14/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This missense variant (p.Pro155Thr) is associated with reduced OATP1B1 transporter function, which can lead to increased plasma concentrations of certain statins and higher risk of myopathy.
A regulatory variant in the SLCO1B1 gene influencing statin pharmacokinetics.
Defines the c.388A>G (p.Asn130Asp) variant, which is a component of the SLCO1B1*1B and *15 haplotypes, influencing hepatic statin uptake.
This variant (c.521T>C) is strongly associated with decreased function of the OATP1B1 transporter, significantly increasing the risk of statin-induced myopathy.
Known as SLCO1B1*1b (p.Asn130Asp), this variant alters hepatic transporter activity and modulates statin exposure and pharmacokinetic clearance.
Defines the SLCO1B1*14 haplotype (p.Gly488Ala) associated with altered hepatic uptake transporter activity and statin pharmacokinetics.