SLCO1B1 rs115668874: What Your Genotype Means
The rs115668874 variant is a genetic polymorphism located within the SLCO1B1 gene, which encodes a protein responsible for transporting medications into the liver. This variant is studied for its potential influence on how the body processes statin medications and its association with statin-associated muscle symptoms.
What each genotype means
Typical transporter function
You carry two copies of the common C allele for this SLCO1B1 variant. Research suggests this baseline genotype is associated with normal hepatic uptake and typical clearance of affected medications, including statins like simvastatin. Statin regimens and dosages should always be reviewed directly with a prescribing physician or pharmacist.
Found in over 97% of individuals across global populations, representing the standard reference genotype in all major ancestries.
Altered transporter activity
You carry one copy of the rare T variant allele in SLCO1B1, often categorized as part of the *14 or related regulatory haplotypes. Published evidence indicates this allele may modify OATP1B1 transporter function and potentially alter hepatic uptake or circulating levels of statins, though evidence strength remains limited. Please consult your physician or pharmacist regarding how your genetic profile might influence statin therapy choices and dosing.
Carried by approximately 1% to 2% of people across most surveyed global ancestry groups.
Atypical transporter activity
You carry two copies of the rare T allele for this SLCO1B1 marker. While clinical evidence specific to the homozygous state is limited, having two copies is predicted to impact OATP1B1 hepatic uptake transport, which could affect blood concentrations and clearance of statin medications such as simvastatin. You should discuss your specific medication choices and dosing strategies with your clinician or pharmacist.
Extremely rare across all global populations, occurring in fewer than 1 in 2,500 individuals.
Understanding the SLCO1B1 Gene
The SLCO1B1 gene provides instructions for making a protein called organic anion-transporting polypeptide 1B1 (OATP1B1). This protein is primarily found in the liver, where it acts as a gatekeeper, helping to move various substances—including bile acids, hormones, and many commonly prescribed medications—from the bloodstream into liver cells. Once inside the liver, these substances can be processed, metabolized, or excreted. Because OATP1B1 is essential for the hepatic uptake of statins, which are widely used to lower cholesterol, the function of this transporter is a major focus of pharmacogenomics. When the OATP1B1 transporter functions less efficiently, certain statins may remain in the bloodstream at higher concentrations for longer periods, which is hypothesized to increase the risk of side effects.
The Role of rs115668874
The rs115668874 variant is a specific change in the DNA sequence of the SLCO1B1 gene. In the context of pharmacogenomics, researchers investigate such variants to determine if they alter the structure or expression of the OATP1B1 protein. While some variants in SLCO1B1, such as rs4149056, are well-established as having a significant impact on statin pharmacokinetics and the risk of muscle-related side effects, the evidence for rs115668874 is considered more limited. It is often categorized as a regulatory polymorphism, meaning it may influence how much of the transporter protein is produced rather than changing the protein's shape directly. Because the evidence linking this specific variant to clinical outcomes is not as robust as that for other known SLCO1B1 variants, it remains a subject of ongoing research to clarify its exact contribution to drug response.
Clinical Significance and Evidence
Current research into SLCO1B1 variants is primarily driven by the goal of improving the safety and efficacy of statin therapy. Statin-associated muscle symptoms (SAMS), which can range from mild muscle aches to rare, severe muscle breakdown, are a known concern for some patients. While clinical guidelines from organizations like the Clinical Pharmacogenetics Implementation Consortium (CPIC) provide actionable recommendations for well-studied variants, rs115668874 does not currently have the same level of clinical consensus. It is important to note that genetic factors are only one piece of the puzzle; other variables, including age, diet, kidney function, and concurrent use of other medications, play significant roles in how a patient responds to statins. If you are concerned about your response to a medication, it is essential to discuss your genetic results and any symptoms with your healthcare provider or pharmacist before making changes to your treatment plan.
Population Frequency
The frequency of the rs115668874 variant varies across different ancestral populations. Like many regulatory polymorphisms, it is found in a significant portion of the population, though its prevalence is not uniform globally. Because genetic diversity is high, the distribution of this variant can differ substantially between individuals of European, African, Asian, and other ancestries. Researchers use large-scale genomic databases to track these frequencies, which helps in understanding the potential impact of the variant on a global scale. However, population frequency alone does not determine an individual's risk, as the interaction between genetics and environment is complex and highly personalized.
How common is this variant?
The rs115668874 variant is common in many populations, though its specific frequency varies significantly depending on ancestral background.
Frequently asked questions
What is the SLCO1B1 gene?
The SLCO1B1 gene encodes the OATP1B1 protein, which helps transport drugs like statins from the blood into the liver. Variations in this gene can affect how quickly these drugs are cleared from your system.
Can this variant predict if I will have muscle pain from statins?
While some SLCO1B1 variants are strongly linked to statin-associated muscle symptoms, the evidence for rs115668874 is limited. Genetic testing is only one factor, and you should always consult your doctor regarding any side effects.
Should I change my medication based on this result?
No. You should never change your medication dosage or stop taking a prescribed drug based on genetic test results without consulting your healthcare provider or a pharmacist.
Where can I find more information on SLCO1B1?
You can explore resources like the CPIC guidelines or the PharmGKB database for evidence-based information on how genetics influences drug response.
Sources & further reading
Educational information only, last refreshed 10/5/2026. 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.
Defines the c.388A>G (p.Asn130Asp) variant, which is a component of the SLCO1B1*1B and *15 haplotypes, influencing hepatic statin uptake.
Non-synonymous coding polymorphism (p.Asn130Asp) defining the SLCO1B1*30 allele with modest alteration in 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.