LDLR rs688: Understanding This Common Genetic Variant
The rs688 variant is a common genetic change located within the LDLR gene, which provides instructions for the low-density lipoprotein receptor. Research has associated this variant with variations in plasma LDL cholesterol levels and potential impacts on how the body processes lipids.
What each genotype means
Typical LDL receptor function
This genotype represents the major allele configuration for the rs688 variant. Research indicates that individuals with this genotype typically exhibit standard LDLR exon 12 splicing efficiency compared to those carrying the minor allele.
This is the most common genotype in many populations, though frequencies vary significantly by ancestry.
Intermediate LDL receptor efficiency
Carrying one copy of the minor allele (T) is associated with increased alternative splicing of LDLR exon 12, which may lead to reduced receptor protein levels at the cell surface. Statistical associations suggest this genotype may contribute to slightly higher plasma LDL cholesterol levels compared to the CC genotype.
This heterozygous genotype is common, appearing in a significant portion of the population across various ancestries.
Reduced LDL receptor efficiency
Individuals with this genotype carry two copies of the minor allele, which has been linked to increased alternative splicing and potential nonsense-mediated decay of LDLR mRNA. Research suggests this may result in lower cell-surface LDLR protein and reduced LDL uptake capacity, potentially predisposing carriers to higher plasma LDL cholesterol levels.
This genotype is observed in populations worldwide, with higher prevalence in European cohorts compared to African populations.
What is the rs688 Variant?
The rs688 variant is a single nucleotide polymorphism (SNP) found in the LDLR gene. Specifically, it is a synonymous variant located in exon 12, meaning that while the DNA sequence changes, the amino acid sequence of the resulting protein remains the same. Despite being synonymous, research indicates that this variant can influence the efficiency of exon splicing. When the splicing process is altered, it may lead to the production of less functional or reduced amounts of the LDL receptor protein. Because this variant sits in a critical region of the gene, scientists have investigated whether these molecular changes contribute to broader physiological differences in how individuals manage cholesterol in their bloodstream.
The Role of the LDLR Gene
The LDLR gene is responsible for producing the low-density lipoprotein receptor, a protein that plays a vital role in cholesterol metabolism. These receptors are primarily found on the surface of liver cells, where they act like docking stations to capture LDL cholesterol from the blood and bring it into the cell for processing. By removing LDL cholesterol from circulation, the LDLR protein helps maintain healthy blood cholesterol levels. When the LDLR gene is functioning optimally, the body can effectively regulate cholesterol. However, if the receptor is absent, reduced in number, or impaired in its ability to bind or recycle, LDL cholesterol can accumulate in the blood, which is a known factor in cardiovascular health.
Research and Associations
Scientific studies have observed associations between the rs688 variant and lipid profiles in various populations. Research suggests that the minor allele of rs688 is linked to increased levels of plasma LDL cholesterol. Beyond simple cholesterol levels, some studies have explored whether this variant affects the receptor's ability to recycle within the cell or interact with proteins like PCSK9, which regulates receptor degradation. Additionally, some research has examined potential sex-dependent associations, including studies looking at the variant's relationship with Alzheimer's disease risk in specific male cohorts. It is important to note that the evidence for these associations is considered limited or mixed across different populations, and the variant is not a diagnostic marker for disease.
Interpreting Your Information
Understanding your genetic variants can be an educational experience, but it is essential to view this information in the proper context. The rs688 variant is common, and its presence does not mean you have a specific medical condition. Many factors, including diet, lifestyle, age, and the cumulative effect of thousands of other genetic variants, contribute to your overall cholesterol levels and cardiovascular health. You cannot use this information to diagnose yourself or predict specific health outcomes. If you are concerned about your cholesterol levels or cardiovascular risk, the most effective step is to consult with a healthcare professional. They can provide personalized guidance based on your clinical blood work and medical history, which are far more predictive of your health than any single genetic variant.
How common is this variant?
The minor allele frequency for rs688 is approximately 0.40-0.45 in European populations and approximately 0.15 in African populations.
Frequently asked questions
Is rs688 a cause of Familial Hypercholesterolemia?
No, rs688 is a common polymorphism and is not considered a primary cause of Familial Hypercholesterolemia, which is typically caused by rare, high-impact pathogenic variants in the LDLR gene.
Should I change my diet based on my rs688 genotype?
You should not make dietary changes based solely on this genetic variant. Always consult with a doctor or a registered dietitian to create a nutrition plan tailored to your specific health needs and blood test results.
Does this variant mean I will have high cholesterol?
Not necessarily. While some studies associate the minor allele with higher LDL cholesterol, many factors influence your cholesterol levels, including your overall genetic background, lifestyle, and environment.
Where can I find more information about my cholesterol risk?
The best source for information regarding your personal cholesterol risk is your primary care physician or a cardiologist. They can interpret your lipid panel 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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Pathogenic missense variant altering low-density lipoprotein receptor function and predisposing to severe familial hypercholesterolemia.
This pathogenic variant in the LDLR gene is a contributor to familial hypercholesterolemia, leading to significantly elevated LDL cholesterol levels.
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A variant in the 3' UTR of the LDLR gene associated with variations in statin therapeutic response.
This variant is a well-established marker associated with LDL cholesterol levels and risk of coronary artery disease.
Familial hypercholesterolemia pathogenic missense variant in the LDL receptor gene causing severe premature cardiovascular risk.