UGT1A1
UDP glucuronosyltransferase family 1 member A1
Theoretical — per Powers
Gene summary
A protein-coding gene on chromosome 2 (steroid conjugation and clearance). Encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases.
Source: NCBI Gene, accessed 2026-10-07.
Protein reference (UniProt)
- Protein
UDP-glucuronosyltransferase 1A1
- Function (excerpt)
Isoform 1: UDP-glucuronosyltransferase (UGT) that catalyzes phase II biotransformation reactions in which lipophilic substrates are conjugated with glucuronic acid to increase the metabolite's water solubility, thereby facilitating excretion into either the urine or bile. Essential for the elimination and detoxification of drugs, xenobiotics and endogenous compounds. Catalyzes the glucuronidation of endogenous estrogen hormones such as estradiol, estrone and estriol. Involved in the glucuronidation of bilirubin, a degradation product occurring in the normal catabolic pathway that breaks down heme in vertebrates. Involved in the glucuronidation of arachidonic acid (AA) and AA-derived eicosanoids including 15-HETE, 20-HETE, PGB1 and F2-isoprostane (8-iso-PGF2alpha). Involved in the glucuronidation of the phytochemical ferulic acid at the phenolic or the carboxylic acid group.
- Subcellular location
Endoplasmic reticulum membrane; Cytoplasm, perinuclear region.
- Tissue specificity
Isoform 1: Expressed in liver, colon and small intestine. Not expressed in kidney, esophagus and skin. Isoform 2: Expressed in liver, colon, small intestine and kidney. Not expressed in esophagus and skin.
- Associated conditions
Gilbert syndrome (GILBS); Transient familial neonatal hyperbilirubinemia (HBLRTFN); Crigler-Najjar syndrome 1 (CN1); Crigler-Najjar syndrome 2 (CN2).
Source: UniProtKB/Swiss-Prot P22309, release 2026_03, licensed CC BY 4.0. This is the protein’s normal biology, not evidence about post-drug syndromes; associated conditions are inherited disorders of the gene, not PFS, PSSD or PRSD.
Why its pathway is in the library
Steroid clearance is the exit route for androgens and their metabolites — the pathway at the center of Powers' PFS model (defective glucuronidation/sulfation trapping androgens intracellularly). Gut bacterial enzymes can undo this clearance, linking it to the microbiome thread.
Written for the whole conjugation & clearance family, not for UGT1A1 specifically.
Powers’ note (his unpublished theorizing)
Covered by Powers' general claim (DWP-002, unpublished) that defective glucuronidation underlies his PFS phenotype (>50% of his PFS patients show ~zero urinary androgens on DUTCH testing); not individually named by him.
Narrative library record
Function
UDP-glucuronosyltransferase that conjugates glucuronic acid onto lipophilic molecules - steroids, bilirubin, hormones, drugs - converting them to water-soluble, excretable metabolites. Over 100 described variants alter its activity (for example, Gilbert syndrome variants).
Corpus relevance
Powers' DWP-002 model centers on broken glucuronidation/excretion: more than half of his PFS patients showed near-zero urinary androgens on DUTCH testing, implicating defective UGT-mediated clearance, and he trialed calcium D-glucarate (a beta-glucuronidase inhibitor) to lower neurosteroid load. UGT1A1 represents the glucuronidation pathway in the library; the androgen-specific clearance work falls mainly to the UGT2B cluster. Attribution: theoretical-per-Powers for the PFS link; the enzyme's clearance role is established.
Mentioned in 6 corpus records
- Gene recordPowers’ theory
AKR1C4 — aldo-keto reductase family 1 member C4
10p15-p14 (AKR1C gene cluster, chromosome 10)
3-alpha-hydroxysteroid dehydrogenase type 1; liver-restricted isoform that reduces 3-keto-5-dihydrosteroids to tetrahydro products and participates in neurosteroid synthesis. Loss of AKR1C4 alone does not cause developmental phenotypes but can worsen the…
AKR1C1AKR1C2AKR1C3AKR1C4UGT1A1+1GENE-AKR1C4Core corpus - Gene recordPowers’ theory
UGT2B7 — UDP glucuronosyltransferase family 2 member B7
chromosome 4 (UGT2B gene cluster, 4q13 region)
Broad-specificity glucuronosyltransferase of the UGT2B cluster that conjugates steroid hormones and many drugs for excretion; handles a wide substrate range including opioids and NSAIDs alongside endogenous steroids.
ABCC2UGT1A1UGT2B15UGT2B17UGT2B7GENE-UGT2B7Core corpus - Gene recordPowers’ theory
UGT2B15 — UDP glucuronosyltransferase family 2 member B15
chromosome 4 (UGT2B gene cluster, 4q13 region)
Androgen-conjugating UGT expressed in liver, prostate, adipose, skin, and other tissues; glucuronidates DHT, androsterone, and androstane-3-alpha,17-beta-diol, directly terminating their activity and marking them for urinary excretion.
AKR1C2ARUGT1A1UGT2B15UGT2B17+1GENE-UGT2B15Core corpus - Gene recordPowers’ theory
Steroid-glucuronidating enzyme of extrahepatic tissues (notably prostate) that conjugates C19 steroids including DHT, androsterone, and 3-alpha-diol; notable for common copy-number variation (whole-gene deletion is frequent) associated in the literature with…
ABCC3UGT1A1UGT2B15UGT2B17UGT2B7GENE-UGT2B17PFSCore corpus - Gene recordPowers’ theory
Apical membrane efflux pump (MRP2) of liver, kidney, and intestine that exports organic anions - including bilirubin glucuronides and drug conjugates - out of cells for elimination. Loss causes Dubin-Johnson syndrome; polymorphisms alter drug pharmacokinetics.
ABCC2ABCC3UGT1A1UGT2B15UGT2B17GENE-ABCC2Core corpus - Gene recordPowers’ theory
Encodes OATP1B1, the sodium-independent organic-anion transporter on liver cell membranes that moves bilirubin, hormones, toxins, and many drugs from blood into the liver for clearance; biallelic loss together with SLCO1B3 causes Rotor syndrome (conjugated…
ABCC2ABCC3SLCO1B1SLCO1B3UGT1A1+2GENE-SLCO1B1PFSCore corpus
Also in steroid conjugation and clearance
All 31 genes- UGT2B17Powers
UDP glucuronosyltransferase family 2 member B17
chr 4· Conjugation & clearance· 30 records - UGT2B15Powers
UDP glucuronosyltransferase family 2 member B15
chr 4· Conjugation & clearance· 13 records - AKR1C2Powers
aldo-keto reductase family 1 member C2
chr 10· Steroid synthesis· 12 records - UGT2B7Powers
UDP glucuronosyltransferase family 2 member B7
chr 4· Conjugation & clearance· 11 records - AKR1C3Powers
aldo-keto reductase family 1 member C3
chr 10· Steroid synthesis· 9 records - AKR1C4Powers
aldo-keto reductase family 1 member C4
chr 10· Steroid synthesis· 8 records - AKR1C1Powers
aldo-keto reductase family 1 member C1
chr 10· Steroid synthesis· 7 records - SULT2A1Powers
sulfotransferase family 2A member 1
chr 19· Conjugation & clearance· 7 records
Browse by family on the gene families page.