Crigler-Najjar syndrome type 1
Findings
No curated finding names Crigler-Najjar syndrome type 1 yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Crigler-Najjar syndrome type 1 (CNS1) is the most severe form of CNS, a hereditary disorder of hepatic bilirubin conjugation, characterized by severe neonatal unconjugated hyperbilirubinemia due to a complete absence of hepatic bilirubin glucuronosyltransferase (BGT).
Definition from the Mondo Disease Ontology (MONDO:0021020), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal recessive inheritance
- Onset and course
- Congenital onset
HPO, annotations 2026-09-02
Features
17 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- JaundiceHPOHP:0000952
- 58 of 58 reported patients
- Unconjugated hyperbilirubinemiaHPOHP:0008282
- 58 of 58 reported patients
- Very frequent (80% to 99% of cases)
- Abnormality of the liverHPOHP:0001392
- Very frequent (80% to 99% of cases)
- Biliary tract abnormalityHPOHP:0001080
- Very frequent (80% to 99% of cases)
- Floppy infantHPOHP:0008947
- Very frequent (80% to 99% of cases)
- KernicterusHPOHP:0001343
- Very frequent (80% to 99% of cases)
Show the remaining 5
- Oculomotor nerve palsyHPOHP:0012246
- Occasional (5% to 29% of cases)
- SeizureHPOHP:0001250
- Occasional (5% to 29% of cases)
- TremorHPOHP:0001337
- Occasional (5% to 29% of cases)
- Elevated circulating hepatic transaminase concentrationHPOHP:0002910
- 0 of 1 reported patient
- EncephalopathyHPOHP:0001298
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- UGT1A1HGNC:12530
- Definitive · Ambry Genetics · Autosomal recessive · 2018
- Definitive · Laboratory for Molecular Medicine · Autosomal recessive · 2020
- Definitive · G2P · Autosomal recessive · 2025
- Strong · PanelApp Australia · Autosomal recessive · 2025
- Supportive · Orphanet · Autosomal recessive · 2021
Where it sits
- A kind of
Other names
7 names
Resolves to: Crigler-Najjar syndrome type 1
- Also called
- bilirubin uridinediphosphate glucuronosyltransferase deficiency type 1bilirubin-UGT deficiency type 1Crigler-Najjar syndrome, type 1Crigler-Najjar syndrome, type Ihereditary unconjugated hyperbilirubinemia type 1hyperbilirubinemia, Crigler-Najjar type 1UGT deficiency type 1