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Primary topic: UGT1A1 detox gene

UGT1A1 Gene and Metabolism: What It Means for Your Body

UGT1A1 is part of the conjugation system that helps package compounds for clearance, including bilirubin and various metabolic byproducts.

What is the UGT1A1 gene?

UGT1A1 encodes an enzyme used in glucuronidation, a detoxification process that makes substances easier to eliminate. It is especially relevant for bilirubin handling but also reflects broader conjugation capacity.

How UGT1A1 affects metabolism

If UGT1A1-related throughput is slower, bilirubin clearance and some detoxification steps may operate with less margin. That can matter when symptom patterns suggest poor tolerance to load, medication sensitivity, or sluggish recovery.

What happens when UGT1A1 is altered

Altered UGT1A1 function often becomes relevant under higher load rather than in everyday conditions. The useful question is whether conjugation markers or bilirubin patterns suggest the pathway is actually active as a constraint.

Curated SNP evidence for UGT1A1

These SNPs come from the approved study-level evidence model. Each claim is scored from curated study rows, then gated before it can influence pathway scoring.

Caffeine / stimulant sensitivity Estrogen metabolism

Evidence-backed report connection

UGT1A1 currently has 3 curated SNPs, 7 claim-level scores, and 5 claims eligible for pathway scoring.

Open the sample report
rs4148323UGT1A1*6 Gly71Arg1 claims · 2 study rows

enzyme activity · A

UGT1A1 glucuronidation activity

Moderate

rs4148323 A, the UGT1A1*6 allele, is associated with reduced UGT1A1 glucuronidation activity.

UGT1A1 rs4148323 is staged as a reduced glucuronidation-capacity allele with relevance to bilirubin and drug glucuronidation.

Likely effectLower enzyme activity signal
Signal sizeSmall signal
Evidence supportModerate support
Report useIncluded in pathway scoring
Show study evidence
NCBI Bookshelf NBK593302clinical curation · directNCBI Medical Genetics Summaries identifies UGT1A1*6 as rs4148323, 211G>A / Gly71Arg, and lists it among UGT1A1 decreased-function alleles; the same summary explains that UGT1A1 glucuronidates bilirubin and many drugs. This supports the A allele as a reduced UGT1A1 activity claim rather than a disease-risk claim.PMCID PMC4775324review · directThe checked review describes UGT1A1*6 (rs4148323) as Gly71Arg, lists A as the variant allele, and states that UGT1A1*6 is associated with reduced activity. It is included only as capped review-level support alongside the NCBI curation.
rs8175347UGT1A1*283 claims · 9 study rows

enzyme activity · 77

UGT1A1 enzyme activity

Strong

rs8175347 77 is associated with reduced UGT1A1 enzyme activity.

UGT1A1 rs8175347 is scored as lower UGT1A1 activity when the 7-repeat allele is present, with the strongest score for 77.

Likely effectLower enzyme activity signal
Signal sizeModerate signal
Evidence supportStrong support
Report useIncluded in pathway scoring
Show study evidence
PubMed 25394086clinical curation · close proxyThe PubMed abstract for this clinical study describes UGT1A1*28 rs8175347 as a promoter TA-repeat polymorphism. It states that 6 TA repeats correspond to normal UGT1A1 activity, while 7 repeats in one or two copies are associated with lower activity and can contribute to higher indirect bilirubin or altered handling of drugs metabolized by UGT1A1.PMC3938665biomarker association · loose proxyA study in healthy North-Europeans found that UGT1A1 rs8175347 TA-repeat genotypes were closely related to bilirubin concentration. The paper reports that TA7/TA7 diplotypes had higher bilirubin than other diplotypes and concludes that the TA7 allele was the predominant UGT1A1 variant responsible for increased bilirubin in that population.PubMed 34866848biomarker association · loose proxyThis PubMed record describes UGT1A1*28 as the 7TA allele in the UGT1A1 promoter and states that the additional TA repeat leads to a significant decrease in liver UGT-1A enzymatic activity and glucuronidation. The abstract also cautions that symptoms and bilirubin alone do not make a definitive Gilbert syndrome diagnosis.

enzyme activity · 67

UGT1A1 enzyme activity

Moderate

rs8175347 67 is associated with reduced UGT1A1 enzyme activity.

UGT1A1 rs8175347 is scored as lower UGT1A1 activity when the 7-repeat allele is present, with the strongest score for 77.

Likely effectLower enzyme activity signal
Signal sizeSmall signal
Evidence supportStrong support
Report useIncluded in pathway scoring
Show study evidence
PubMed 25394086clinical curation · close proxyThe PubMed abstract for this clinical study describes UGT1A1*28 rs8175347 as a promoter TA-repeat polymorphism. It states that 6 TA repeats correspond to normal UGT1A1 activity, while 7 repeats in one or two copies are associated with lower activity and can contribute to higher indirect bilirubin or altered handling of drugs metabolized by UGT1A1.PMC3938665biomarker association · loose proxyA study in healthy North-Europeans found that UGT1A1 rs8175347 TA-repeat genotypes were closely related to bilirubin concentration. The paper reports that TA7/TA7 diplotypes had higher bilirubin than other diplotypes and concludes that the TA7 allele was the predominant UGT1A1 variant responsible for increased bilirubin in that population.PubMed 34866848biomarker association · loose proxyThis PubMed record describes UGT1A1*28 as the 7TA allele in the UGT1A1 promoter and states that the additional TA repeat leads to a significant decrease in liver UGT-1A enzymatic activity and glucuronidation. The abstract also cautions that symptoms and bilirubin alone do not make a definitive Gilbert syndrome diagnosis.

enzyme activity · 66

UGT1A1 enzyme activity

Not used for pathway scoring

rs8175347 66 has no scored directional claim for UGT1A1 enzyme activity.

UGT1A1 rs8175347 is scored as lower UGT1A1 activity when the 7-repeat allele is present, with the strongest score for 77.

Likely effectNo clear enzyme signal
Signal sizeMinimal signal
Evidence supportVery limited support
Report useEvidence only, not scored
Show study evidence
PubMed 25394086clinical curation · close proxyThe PubMed abstract for this clinical study describes UGT1A1*28 rs8175347 as a promoter TA-repeat polymorphism. It states that 6 TA repeats correspond to normal UGT1A1 activity, while 7 repeats in one or two copies are associated with lower activity and can contribute to higher indirect bilirubin or altered handling of drugs metabolized by UGT1A1.PMC3938665biomarker association · loose proxyA study in healthy North-Europeans found that UGT1A1 rs8175347 TA-repeat genotypes were closely related to bilirubin concentration. The paper reports that TA7/TA7 diplotypes had higher bilirubin than other diplotypes and concludes that the TA7 allele was the predominant UGT1A1 variant responsible for increased bilirubin in that population.PubMed 34866848biomarker association · loose proxyThis PubMed record describes UGT1A1*28 as the 7TA allele in the UGT1A1 promoter and states that the additional TA repeat leads to a significant decrease in liver UGT-1A enzymatic activity and glucuronidation. The abstract also cautions that symptoms and bilirubin alone do not make a definitive Gilbert syndrome diagnosis.
rs887829UGT1A1 supporting signal3 claims · 9 study rows

biomarker tendency · TT

UGT1A1 biomarker tendency

Strong

rs887829 TT is associated with increased UGT1A1 biomarker tendency.

UGT1A1-region rs887829 is scored as a higher bilirubin tendency when the T allele is present, with a stronger score for TT than CT.

Likely effectHigher biomarker tendency
Signal sizeSmall signal
Evidence supportStrong support
Report useIncluded in pathway scoring
Show study evidence
NCBI RefSNP recordidentity only · unknownNCBI RefSNP places rs887829 in the UGT1A gene region and annotates it upstream of UGT1A1, with C and T as the common allele labels in population datasets. This supports a UGT1A1-region biomarker-tendency record rather than a direct coding enzyme-change record.PMC3306855gwas · close proxyA genome-wide study in African Americans found that UGT1A1 was a major locus for serum total bilirubin. The strongest signal was rs887829, and the paper reports that each copy of the T allele was associated with higher serum bilirubin in both prior European evidence and the African American cohort.PMC10451688gwas · close proxyA Danish child and adolescent GWAS reported rs887829 as the most significant bilirubin-associated SNP in its analysis and notes that this marker is located in the UGT1A1*28 locus, which has been strongly and positively associated with circulating bilirubin in adults.

biomarker tendency · CT

UGT1A1 biomarker tendency

Moderate

rs887829 CT is associated with increased UGT1A1 biomarker tendency.

UGT1A1-region rs887829 is scored as a higher bilirubin tendency when the T allele is present, with a stronger score for TT than CT.

Likely effectHigher biomarker tendency
Signal sizeSmall signal
Evidence supportStrong support
Report useIncluded in pathway scoring
Show study evidence
NCBI RefSNP recordidentity only · unknownNCBI RefSNP places rs887829 in the UGT1A gene region and annotates it upstream of UGT1A1, with C and T as the common allele labels in population datasets. This supports a UGT1A1-region biomarker-tendency record rather than a direct coding enzyme-change record.PMC3306855gwas · close proxyA genome-wide study in African Americans found that UGT1A1 was a major locus for serum total bilirubin. The strongest signal was rs887829, and the paper reports that each copy of the T allele was associated with higher serum bilirubin in both prior European evidence and the African American cohort.PMC10451688gwas · close proxyA Danish child and adolescent GWAS reported rs887829 as the most significant bilirubin-associated SNP in its analysis and notes that this marker is located in the UGT1A1*28 locus, which has been strongly and positively associated with circulating bilirubin in adults.

biomarker tendency · CC

UGT1A1 biomarker tendency

Not used for pathway scoring

rs887829 CC has no scored directional claim for UGT1A1 biomarker tendency.

UGT1A1-region rs887829 is scored as a higher bilirubin tendency when the T allele is present, with a stronger score for TT than CT.

Likely effectNo clear biomarker tendency
Signal sizeMinimal signal
Evidence supportVery limited support
Report useEvidence only, not scored
Show study evidence
NCBI RefSNP recordidentity only · unknownNCBI RefSNP places rs887829 in the UGT1A gene region and annotates it upstream of UGT1A1, with C and T as the common allele labels in population datasets. This supports a UGT1A1-region biomarker-tendency record rather than a direct coding enzyme-change record.PMC3306855gwas · close proxyA genome-wide study in African Americans found that UGT1A1 was a major locus for serum total bilirubin. The strongest signal was rs887829, and the paper reports that each copy of the T allele was associated with higher serum bilirubin in both prior European evidence and the African American cohort.PMC10451688gwas · close proxyA Danish child and adolescent GWAS reported rs887829 as the most significant bilirubin-associated SNP in its analysis and notes that this marker is located in the UGT1A1*28 locus, which has been strongly and positively associated with circulating bilirubin in adults.

Common symptoms people report

  • feeling sensitive to chemical or medication load
  • slow recovery after higher stress or exposure
  • episodes of higher bilirubin on labs
  • uncertainty around detox support strategies

Biomarkers to validate

Total and direct bilirubin

Most direct way to assess whether bilirubin handling looks unusual.

ALT and AST

Useful baseline liver context when detoxification questions arise.

GGT

Adds context for hepatic load and glutathione-related stress.

Where DNA analysis helps

DNA can prioritize conjugation pathways like UGT1A1 when symptoms or lab patterns suggest clearance issues. It should guide what to measure, not replace measurement.

Example Insight

Your conjugation pathway may have less reserve under chemical or oxidative load.

Suggested validation: total/direct bilirubin and GGT.

What to do next

  • Review bilirubin and liver markers before using broad detox narratives.
  • Compare UGT1A1 with NAT2 and GPX1 when clearance and oxidative load overlap.
  • Use follow-up labs to decide whether the pathway deserves active management.

Upload your DNA file and receive a structured metabolic pathway analysis with prioritized insights and suggested validation markers.

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Estrogen metabolism and clearance pathway

estrogen metabolism clearance pathway

How accurate are DNA metabolism reports?

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Best DNA test for metabolism

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Related symptom angle

Poor detoxification symptoms

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