Crigler-Najjar syndrome
Findings
No curated finding names Crigler-Najjar syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Crigler-Najjar syndrome (CNS) is a hereditary disorder of bilirubin metabolism characterized by unconjugated hyperbilirubinemia due to a hepatic deficit of bilirubin glucuronosyltransferase (GT) activity. Two types have been described, CNS types 1 and 2. CNS1 is characterized by a complete deficit of the enzyme and is unaffected by phenobarbital induction therapy, whereas the enzymatic deficit is partial and responds to phenobarbital in CNS2.
Definition from the Mondo Disease Ontology (MONDO:0009044), read 2026-09-29. CC BY 4.0.
Features
22 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
- Very frequent (80% to 99% of cases)
- Neonatal hyperbilirubinemiaHPOHP:0003265
- Very frequent (80% to 99% of cases)
- Unconjugated hyperbilirubinemiaHPOHP:0008282
- Very frequent (80% to 99% of cases)
- HypotoniaHPOHP:0001252
- Frequent (30% to 79% of cases)
- Poor suckHPOHP:0002033
- Frequent (30% to 79% of cases)
- Abnormal auditory evoked potentialsHPOHP:0006958
- Occasional (5% to 29% of cases)
- Cognitive impairment
Show the remaining 10
- High-pitched cryHPOHP:0025430
- Occasional (5% to 29% of cases)
- Infectious encephalitisHPOHP:0002383
- Occasional (5% to 29% of cases)
- KernicterusHPOHP:0001343
- Occasional (5% to 29% of cases)
- LethargyHPOHP:0001254
- Occasional (5% to 29% of cases)
- Memory impairmentHPOHP:0002354
- Occasional (5% to 29% of cases)
- OphthalmoparesisHPOHP:0000597
- Occasional (5% to 29% of cases)
Where it sits
- Narrower terms (2)
Other names
6 names
Resolves to: Crigler-Najjar syndrome
- Also called
- bilirubin UDP glucuronyl transferase deficiencybilirubin uridinediphosphate glucuronosyltransferase deficiencybilirubin-UGT deficiencyCrigler Najjar Syndromehereditary unconjugated hyperbilirubinemiaUGT deficiency