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ORPHA:79234

Crigler-Najjar syndrome type 1

low confidenceSubtype of disorder

Also known as: Bilirubin uridinediphosphate glucuronosyltransferase deficiency type 1 · Bilirubin-UGT deficiency type 1

Publications

11,678

Trials

1

Interventional, condition-specific

Researchers

1,243

Distinct authors in sample

Gene link

UGT1A1

Definitive

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A form of Crigler Najjar syndrome (CNS), a disorder of hepatic bilirubin conjugation, characterized by severe unconjugated hyperbilirubinemia due to a complete absence of hepatic UDP-glucuronosyltransferase 1A1. The disorder clinically manifests with , isolated, severe and permanent jaundice with a permanent risk of bilirubin .

How rare: How common this is has not been clearly measured.

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Additional Mondo synonyms (7)

Crigler-Najjar syndrome, type 1 · Crigler-Najjar syndrome, type I · UGT deficiency type 1 · bilirubin uridinediphosphate glucuronosyltransferase deficiency type 1 · bilirubin-UGT deficiency type 1 · hereditary unconjugated hyperbilirubinemia type 1 · hyperbilirubinemia, Crigler-Najjar type 1

Research stages

Trial readiness signals

Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”

4/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedPresent

    Definitive — UGT1A1

  2. LiteraturePresent

    11,678 matched papers (6,834 in last 10 years) Source

  3. Phenotype characterisedPresent

    19 HPO annotations (e.g. Kernicterus; Elevated circulating hepatic transaminase concentration; Encephalopathy) Source

  4. Animal modelNot found

    No Alliance genotype “model of” associations via Monarch for these Mondo IDs

  5. Orphan designationNot found

    No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source

  6. Interventional trialPresent

    1 matched on ClinicalTrials.gov (1 recruiting in sample)

Biology

Genes and phenotypes

Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.

Do we know what causes it?

Yes — we know a specific gene responsible (UGT1A1).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

19

Associated phenotypes · MONDO:0021020

  • Kernicterus
  • Elevated circulating hepatic transaminase concentration
  • Encephalopathy
  • Jaundice
  • Unconjugated hyperbilirubinemia

Showing 5 of 19 — open Monarch for the full list.

Animal models (Monarch / Alliance)

None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.

Monarch fetch 2026-07-29

Therapies

Designations, candidates, and chemicals

FDA OOPD and EMA orphan designations, Open Targets clinical candidates, and CTD chemical associations via MyDisease.info. These never change the interventional-trial headline.

Orphan designation (FDA · EMA)

No designation matched this disease via UMLS or preferred name on the FDA OOPD mirror or EMA orphan register. Absence here is not proof that none exists under another wording.

Open Targets candidates

No drugs or clinical candidates returned for this Mondo ID on Open Targets.

CTD chemicals (MyDisease.info)

No CTD chemical associations returned for this Mondo ID.

Literature

Is anyone studying this?

11,678

11,678 papers — among the better-studied rare conditions, though still a fraction of common-disease literature (breast cancer: over 700,000). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

11,678 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 59 (publications denominator n=3967).

6,834 in the last 10 years · low confidence

Phrase hits: 443 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,243

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Dhawan A8 papers · 2024

    Dhawan Lab, Paediatric Liver GI and Nutrition Center and MowatLabs, Institute of Liver Studies, King's College London at King's College Hospital, London SE5 9PJ, UK anil.dhawan@kcl.ac.uk.

    Papers in Europe PMC
  2. 02
    Roy-Chowdhury J8 papers · 2019

    Department of Medicine, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York; Department of Genetics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.

    Papers in Europe PMC
  3. 03
    Roy-Chowdhury N7 papers · 2019

    Department of Medicine, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10467, USA.

    Papers in Europe PMC
  4. 04
    Ghosh SS6 papers · 2005

    Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

    Papers in Europe PMC
  5. 05
    Guha C6 papers · 2019

    Department of Pathology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York; Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York; Department of Urology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York. Electronic address: cguhamd@gmail.com.

    Papers in Europe PMC
  6. 06
    Rela M6 papers · 2025

    Department of Child Health, King's College Hospital, London, United Kingdom.

    Papers in Europe PMC
  7. 07
    Bortolussi G5 papers · 2024

    International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.

    Papers in Europe PMC
  8. 08
    Bosma PJ5 papers · 2024

    Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands.

    Papers in Europe PMC
  9. 09
    Muro AF5 papers · 2024

    International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy muro@icgeb.org.

    Papers in Europe PMC
  10. 10
    Nguyen TH5 papers · 2024

    Department of Microbiology and Molecular Medicine, University of Geneva Medical Center, Geneva, Switzerland, and Service de biochimie, Hôpital Saint Joseph, Paris, France. Tuan.Nguyen@medecine.unige.ch

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

1

interventional trials for this specific condition

1 interventional trial matched this specific condition name; 1 currently recruiting in our sample. 6 trials are registered for Crigler-Najjar syndrome, the broader category — shown separately because they may or may not enrol this specific subtype.

Data as of 11 September 2026 · last trial check 28 July 2026

1 interventional trial — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 80.1th percentile).

low confidence · 80.1th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

1 interventional trials matched after quoted-phrase search and title/condition post-filter.

Broader category: Crigler-Najjar syndrome

6

Interventional trials for the parent category, exclusive of NCT IDs already counted above. Eligibility for this subtype is not guaranteed.

Worth raising with a clinician. How we count trials.

Recruiting under the broader category

Other registries (secondary)

Broader net from EU CTIS, ISRCTN, and ICTRP when available — deduped against ClinicalTrials.gov IDs already counted above. Dual-model LLM relevance gates what we keep. These rows are not added to the interventional headline.

raw 1 · after dedupe 1 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 1 · dropped 0 · fetched 2026-07-30

Source notes: ictrp: Error: ICTRP public search unavailable (WHO portal is SPA-only; SOAP needs partnership). Tried: https://apps.who.int/tri

No secondary-registry studies passed dual-model relevance for this condition name (after dedupe).

Uncertain / not reviewed (1)

Where to find support

Condition-specific patient organisations, when Orphanet lists them, are on the disease’s Orphanet page. We also link umbrella groups that support undiagnosed and ultra-rare families.

Orphanet entry for Crigler-Najjar syndrome type 1 — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.

Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.

How we counted this

Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.

("Crigler-Najjar syndrome type 1" OR "Bilirubin uridinediphosphate glucuronosyltransferase deficiency type 1" OR "Bilirubin-UGT deficiency type 1" OR "Crigler-Najjar syndrome, type 1" OR "Crigler-Najjar syndrome, type I" OR "UGT deficiency type 1" OR "hereditary unconjugated hyperbilirubinemia type 1" OR "hyperbilirubinemia, Crigler-Najjar type 1") OR ("UGT1A1" OR "UGT1A1 syndrome" OR "UGT1A1-related")

Run this search on Europe PMC

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"Crigler-Najjar syndrome type 1" OR "Bilirubin uridinediphosphate glucuronosyltransferase deficiency type 1" OR "Bilirubin-UGT deficiency type 1" OR "Crigler-Najjar syndrome, type 1" OR "Crigler-Najjar syndrome, type I" OR "UGT deficiency type 1" OR "hereditary unconjugated hyperbilirubinemia type 1" OR "hyperbilirubinemia, Crigler-Najjar type 1"

Interventional trials matched via: phrase (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 1 interventional · 0 observational · 0 expanded access. Only interventional studies enter the trial headline.

Parent-category trials query:

"Crigler-Najjar syndrome"

Query health: ok — strategies attempted: phrase; with hits: phrase

Run this search on ClinicalTrials.gov

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus
  • Publication count (11678) is extremely high with unknown/missing prevalence — treat as possible over-matching, not proven research intensity

Ingested 2026-07-27T02:06:19.586Z