ORPHA:79235
Crigler-Najjar syndrome type 2
Also known as: Bilirubin uridinediphosphate glucuronosyltransferase deficiency type 2 · Bilirubin-UGT deficiency type 2
Publications
63
46.9th percentile
Trials
19
Interventional, condition-specific
Researchers
332
Distinct authors in sample
Gene link
UGT1A1
Definitive
Readiness
3/6
Stages with a signal
Clinical definition (Orphanet)
A form of Crigler Najjar syndrome (CNS), a rare disorder of bilirubin metabolism, characterized by unconjugated hyperbilirubinemia due to reduced and inducible activity of hepatic UDP-glucuronosyltransferase 1A1. The disorder clinically manifests with , isolated jaundice with a risk of developing bilirubin later in life due to triggers such as stress or infection.
How rare: How common this is has not been clearly measured.
Cross-references
Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.
- MONDO:0011725
- MeSH:C536213
- OMIM:606785
- UMLS:C2931132
Additional Mondo synonyms (5)
Arias syndrome · UGT deficiency type 2 · bilirubin uridinediphosphate glucuronosyltransferase deficiency type 2 · bilirubin-UGT deficiency type 2 · hereditary unconjugated hyperbilirubinemia type 2
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.”
3/6 stages with a signal
An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.
- Gene identifiedPresent
Definitive — UGT1A1
- LiteraturePresent
63 matched papers (35 in last 10 years) Source
- Phenotype characterisedNot checked
Not yet enriched from Monarch / HPO
- Animal modelNot checked
Not yet enriched from Monarch / Alliance
- Orphan designationNot checked
FDA/EMA orphan-drug designation not enriched yet
- Interventional trialPresent
19 matched on ClinicalTrials.gov (5 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)
Not enriched in this build — Monarch phenotype joins were not run for this record.
Animal models (Monarch / Alliance)
Not enriched in this build.
Literature
Is anyone studying this?
63
63 papers have ever been published on this condition (under this name). For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=5449) is 41.
63 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 41 (publications denominator n=5449).
35 in the last 10 years · high confidence · 46.9th percentile (publications denominator)
Phrase hits: 63 · MeSH hits: 2
Who's working on it?
332
Distinct author names in 63 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.
- 01Huang CS5 papers · 2024
Department of Clinical Pathology, Cathay General Hospital, Taipei, Taiwan.
Papers in Europe PMC - 02Huang MJ4 papers · 2022
Department of Laboratory Medicine, Cathay General Hospital, 280, Jen Ai-Road, Section 4, Taipei 106, Taiwan, China.
Papers in Europe PMC - 03Saxena R4 papers · 2017
Department of Genetic Medicine, Sir Ganga Ram Hospital, New Delhi, India.
Papers in Europe PMC - 04
- 05Adachi Y2 papers · 2006Papers in Europe PMC
- 06Araki J2 papers · 2006Papers in Europe PMC
- 07Burchell B2 papers · 2001Papers in Europe PMC
- 08Chen PL2 papers · 2022
Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
Papers in Europe PMC - 09Chen X2 papers · 2025
Department of Chest Surgery, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, China.
Papers in Europe PMC - 10Chen Y2 papers · 2025
Department of Chest Surgery, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, China.
Papers in Europe PMC
Clinical research
Is a treatment being tested?
19
interventional trials for this specific condition
19 interventional trials matched this specific condition name; 5 currently recruiting in our sample. 7 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 27 July 2026
19 interventional trials — more than 73% of diseases in the trials denominator have none at all (5114 of 7003; this disease is at the 94.2th percentile).
high confidence · 94.2th percentile (trials denominator)
Recruiting interventional trials
From the matched ClinicalTrials.gov set
19 interventional trials matched after quoted-phrase search and title/condition post-filter.
- NCT05148767·RECRUITING·UGT1A1-Based Irinotecan Therapy for Locally Advanced Rectal Cancer
Conditions: Rectal Cancer Stage III·Matched via recall expansion
- NCT06760117·RECRUITING·UGT1A1 Genotype-drien Phase I Study of Irinotecan in VIT Regimen for the Treatment of Pediatric R/R Solid Tumors
Conditions: Pediatric Solid Tumor·Matched via recall expansion
- NCT06210971·RECRUITING·Neoadjuvant Chemoradiation With Nal-IRI and Capecitabine Guided by UGT1A1 Status in Patients With Rectal Cancer
Conditions: Rectal Cancer·Matched via recall expansion
- NCT05929885·RECRUITING·Metronomic Capecitabine, Oxaliplatin and UGT1A1 Genotype-directed Irinotecan in Metastatic Pancreatic Cancer Patients
Conditions: Metastatic Pancreatic Cancer·Matched via recall expansion
- NCT06406465·RECRUITING·A UGT1A1 Genotype-Directed Study of Belinostat Pharmacokinetics and Toxicity
Conditions: Carcinoma, Neuroendocrine · Tumor, Neuroendocrine · Tumors, Neuroendocrine · Neuroendocrine; Carcinoma·Matched via recall expansion
Broader category: Crigler-Najjar syndrome
7
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
- NCT06518005·RECRUITING·Efficacy and Safety of GNT0003 Following Imlifidase Pre-treatment in Severe Crigler-Najjar Syndrome
Conditions: Crigler-Najjar Syndrome·Matched via name phrase
- NCT06641154·RECRUITING·Gene Therapy for Crigler Najjar Syndrome Type I (AlphaCN)
Conditions: Crigler-Najjar Syndrome Type I·Matched via name phrase
- NCT03466463·RECRUITING·Gene Therapy for Severe Crigler Najjar Syndrome
Conditions: Crigler-Najjar Syndrome·Matched via name phrase
Observational and natural-history studies
6 observational studies match this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.
Recruiting or not-yet-recruiting
- NCT05655780·RECRUITING·The Role of the Tumor Molecular Profile (CMS), UGT1A1 Genotype and Beta-glucuronidase Activity of the Intestinal Microbiota for Treatment Efficiency, Toxicity, Survival and Quality of Life in Patients With Metastatic or Unresectable Colorectal Cancer During Irinotecan-based Systemic Treatment
Conditions: Colorectal Neoplasms·Matched via recall expansion
- NCT07702630·NOT YET RECRUITING·ABCG8, UGT1A1 and Gallstone Disease After Bariatric Surgery
Conditions: Gallstone Disease · Bariatric Surgery · Metabolic Surgery · Cholecystectomy·Matched via recall expansion
- NCT07582887·RECRUITING·Impact of Genetic Variants on the Toxicity of Antibody-Drug Conjugates in Locally Advanced or Metastatic Breast Cancer: The Role of the UGT1A1 Gene as a Predictive Biomarker of Therapeutic Response
Conditions: Breast Cancer · Metastatic Breast Cancer · Drug-Related Side Effects and Adverse Reactions · Pharmacogenetic Variant·Matched via recall expansion
Where to find support
We do not yet link condition-specific patient organisations. These umbrella groups support undiagnosed and ultra-rare families:
India — NPRD
Last verified 2026-07-26This 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 2" OR "Bilirubin uridinediphosphate glucuronosyltransferase deficiency type 2" OR "Bilirubin-UGT deficiency type 2" OR "Arias syndrome" OR "UGT deficiency type 2" OR "hereditary unconjugated hyperbilirubinemia type 2"
MeSH descriptor terms unioned into the query: Crigler Najjar syndrome, type 2
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Crigler-Najjar syndrome type 2" OR "Bilirubin uridinediphosphate glucuronosyltransferase deficiency type 2" OR "Bilirubin-UGT deficiency type 2" OR "Arias syndrome" OR "UGT deficiency type 2" OR "hereditary unconjugated hyperbilirubinemia type 2" OR "Crigler Najjar syndrome, type 2" OR "UGT1A1"
Recall-expansion terms: UGT1A1
Interventional trials matched via: recall-expansion (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).
Study-type breakdown: 19 interventional · 6 observational · 0 expanded access. Only interventional studies enter the trial headline.
Parent-category trials query:
"Crigler-Najjar syndrome"
Query health: ok — strategies attempted: phrase, mesh, recall-expansion; with hits: phrase, mesh, recall-expansion
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
Ingested 2026-07-27T02:06:29.121Z