UGT1A1 rs887829: What Your Genotype Means for Bilirubin Levels
The rs887829 variant is a single nucleotide polymorphism located in the UGT1A1 gene, which plays a critical role in how the body processes bilirubin. Research indicates that this variant is significantly associated with variations in serum bilirubin concentrations across different populations.
What each genotype means
Typical bilirubin metabolism
This genotype is associated with standard UGT1A1 enzyme activity levels. Individuals with this profile typically maintain serum bilirubin concentrations within the expected range for the general population.
This is the most common genotype in many global populations, though frequencies vary significantly by ancestry.
Intermediate bilirubin metabolism
This genotype represents a heterozygous state often associated with intermediate UGT1A1 enzyme activity. You may have slightly higher serum bilirubin levels compared to those with the CC genotype, though this is generally considered a normal physiological variation.
This genotype is frequently observed across diverse populations, representing a common carrier state for the T allele.
Reduced enzyme activity
This genotype is associated with reduced UGT1A1 enzyme activity and is linked to higher serum bilirubin concentrations. In some individuals, this profile is associated with Gilbert syndrome, a benign condition characterized by mild, intermittent jaundice; please discuss any concerns regarding bilirubin levels or medication metabolism with your clinician or pharmacist.
This genotype is found in approximately 34.2% of the Native American component of the GOCS study and is observed at varying frequencies globally.
Understanding the rs887829 Variant
The rs887829 variant is a specific genetic change, or single nucleotide polymorphism (SNP), located within the UGT1A1 gene region on chromosome 2. In genetics, a SNP represents a variation at a single position in the DNA sequence among individuals. This particular variant has been the subject of extensive study due to its proximity to the UGT1A1 gene, which is essential for the body's metabolic processes. By analyzing this specific location, researchers can better understand how subtle differences in our genetic code contribute to the diversity of physiological traits observed in humans. While rs887829 is just one of many variants in the human genome, its consistent association with metabolic markers makes it a significant point of interest in genomic research.
The Role of the UGT1A1 Gene
The UGT1A1 gene provides the instructions for creating an enzyme called UDP-glucuronosyltransferase. This enzyme is primarily responsible for a process known as glucuronidation, which is a chemical reaction that makes various substances—including bilirubin, hormones, and certain medications—more water-soluble so they can be easily excreted from the body. Bilirubin is a yellow pigment formed during the normal breakdown of red blood cells. If the UGT1A1 enzyme is not functioning at optimal levels, bilirubin can accumulate in the blood, leading to higher serum concentrations. Because this enzyme is so central to detoxification and waste removal, variations in the UGT1A1 gene are frequently studied to understand how individuals differ in their ability to process these substances.
Research and Evidence Strength
Scientific research has established a moderate to strong association between the rs887829 variant and serum bilirubin levels. Studies have shown that this variant can account for a notable percentage of the variance in total bilirubin levels, particularly in specific ancestral groups. For instance, research in pediatric populations has highlighted that the TT genotype is associated with significantly increased serum bilirubin concentrations compared to other genotypes. While the evidence linking this SNP to bilirubin levels is robust, it is important to note that genetic associations can vary based on ancestry and environmental factors. The scientific community continues to investigate how this variant interacts with other genetic markers and physiological conditions to influence overall health outcomes.
Population Frequency and Diversity
The frequency of the rs887829 variant varies significantly across different global populations, which is a common theme in human genetics. For example, data from the GOCS study indicates a frequency of 34.2% for this variant within the Native American component of the population. Because allele frequencies are not uniform worldwide, the impact of this variant on a population level can differ depending on the genetic background of the group being studied. Understanding these frequency differences is crucial for researchers who aim to provide accurate genetic insights that are relevant to diverse communities. As more genomic data becomes available from underrepresented populations, our understanding of how common this variant is globally will continue to become more precise.
Interpreting Your Genetic Information
It is important to remember that genetic variants like rs887829 are only one piece of a much larger biological puzzle. Most human traits and health conditions are influenced by a complex interplay of hundreds or even thousands of genetic variants, as well as lifestyle and environmental factors. Consequently, a single SNP should never be used in isolation to make health decisions or predictions. If you have questions about your bilirubin levels or how your genetics might influence your response to specific medications, it is essential to consult with a qualified healthcare provider or a pharmacist. They can interpret your results in the context of your overall health history and provide guidance that is tailored to your specific needs.
How common is this variant?
The rs887829 variant shows significant variation across ancestries, with a reported frequency of 34.2% in the Native American component of the GOCS study.
Frequently asked questions
What does the rs887829 variant do?
The rs887829 variant is a genetic marker located near the UGT1A1 gene. It is associated with differences in how the body processes bilirubin, which can lead to variations in serum bilirubin levels.
Is rs887829 a cause of disease?
While rs887829 is associated with bilirubin levels, it is not a direct cause of disease on its own. Genetic traits are complex, and most conditions are influenced by many factors, including other genes and the environment.
Should I be worried if I have the TT genotype?
The TT genotype is associated with higher bilirubin levels, but this does not necessarily indicate a health problem. You should discuss your results with a healthcare professional who can evaluate your levels in the context of your overall health.
Can this variant affect how I process medications?
The UGT1A1 gene is involved in processing certain drugs. If you are concerned about how your genetics might affect your medication response, please speak with your doctor or pharmacist before making any changes to your treatment.
Sources & further reading
Educational information only, last refreshed 9/20/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Missense alteration associated with reduced glucuronidation capacity and increased susceptibility to irinotecan toxicity and hyperbilirubinemia.
This variant in the UGT1A gene cluster is associated with serum total bilirubin levels and susceptibility to Gilbert syndrome.
Defines the decreased-function UGT1A1*6 missense allele (p.Gly71Arg), widely implicated in East Asian populations in severe irinotecan-induced neutropenia and neonatal hyperbilirubinemia.
Variant allele in UGT1A1 (defining UGT1A1*60 in the promoter region) associated with altered glucuronidation and elevated risk of irinotecan-induced neutropenia and hyperbilirubinemia.
Missense variant corresponding to the functional UGT1A1*27 allele associated with reduced glucuronidation and elevated irinotecan toxicity risk.