Gilbert syndrome: genes and variants
Gilbert syndrome is linked to 1 analyzed protein (UGT1A1). 10 DNA variants are known to cause it; 28 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Gilbert syndrome
UGT1A1: UDP-glucuronosyltransferase 1A1
It conjugates bilirubin and many lipophilic compounds with glucuronic acid, enabling efficient elimination in bile or urine. Reduced activity causes Gilbert syndrome or Crigler-Najjar syndrome and can also increase toxicity from drugs such as irinotecan.
10 disease-causing and 28 uncertain variants in UGT1A1 are linked to Gilbert syndrome.
Weakly linked (only a few uncertain records): SLCO1B1.
Known disease-causing variants in Gilbert syndrome
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| UGT1A1 G308E | 308 | Disease-causing (★★) | |
| UGT1A1 R209W | 209 | Disease-causing (★★) | |
| UGT1A1 P387R | 387 | Disease-causing (★★) | |
| UGT1A1 Y486D | 486 | Disease-causing (★★) | |
| UGT1A1 Q331R | 331 | Disease-causing (★★) | |
| UGT1A1 C177Y | 177 | Disease-causing (★★) | |
| UGT1A1 Q357R | 357 | Disease-causing (★★) | |
| UGT1A1 L15R | 15 | Disease-causing (★) | |
| UGT1A1 F83L | 83 | Disease-causing (★) | |
| UGT1A1 S306F | 306 | Disease-causing |
Which prediction tools work for Gilbert syndrome
How often each tool ranks a disease-causing variant above a harmless one (AUROC × 100).
- REVEL: 99 out of 100 (learned from overlapping clinical labels, so this is optimistic)
- CATVariant: 98 out of 100 (learned from overlapping clinical labels, so this is optimistic)
- CADD: 98 out of 100
- SIFT: 94 out of 100
- phyloP: 92 out of 100
- PolyPhen-2: 92 out of 100 (learned from overlapping clinical labels, so this is optimistic)
Same protein, different disease
- Crigler-Najjar syndrome is also caused by UGT1A1 variants; they fall mostly in different places as the Gilbert syndrome variants (14 disease-causing).
Diseases related to Gilbert syndrome
- Crigler-Najjar syndrome, also linked to UGT1A1
- Lucey-Driscoll syndrome, also linked to UGT1A1
- BILIRUBIN, SERUM LEVEL OF, QUANTITATIVE TRAIT LOCUS 1, also linked to UGT1A1
Frequently asked questions
Which genes are linked to Gilbert syndrome?
In CATVariant, Gilbert syndrome is linked to 1 analyzed protein: UGT1A1 (UDP-glucuronosyltransferase 1A1).
How many genetic variants are linked to Gilbert syndrome?
53 variants: 10 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 28 are of uncertain significance or have conflicting reports.
Which uncertain variants in Gilbert syndrome look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
Which variant effect predictor works best for Gilbert syndrome?
Among tools not trained on clinical labels, CADD separates this disease's known disease-causing variants from harmless ones best (AUROC 0.98, based on 9 disease-causing and 11 harmless variants).
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
Download every variant as CSV · Browse all diseases · Methods · About the Center