Overview
Crigler-Najjar syndrome type 1 (also called CN1 or Crigler-Najjar type I) is a very rare, serious liver disorder that a person is born with. It affects how the body processes bilirubin — a yellow substance made when red blood cells break down. Normally, the liver converts bilirubin into a form that can leave the body through bile. In Crigler-Najjar type 1, the liver enzyme responsible for this process (called UGT1A1) is completely absent or does not work at all. This causes bilirubin to build up to dangerous levels in the blood, a condition called hyperbilirubinemia. The most visible sign is jaundice — a yellow coloring of the skin and eyes — which appears within the first few days of life and never goes away without treatment. The biggest danger is that high bilirubin can cross into the brain and cause permanent brain damage, a condition called kernicterus or bilirubin encephalopathy. This can lead to problems with movement, hearing, and thinking. The main treatment is phototherapy — exposing the skin to special blue lights for 10 to 16 hours every day. This helps break down bilirubin in the skin but does not cure the disease. The only cure currently available is a liver transplant, which replaces the non-working liver with one that can process bilirubin normally. Gene therapy is being actively studied as a future treatment option. Without treatment, this condition is life-threatening in early childhood.
Also known as:
Key symptoms:
Persistent yellow skin and eyes (jaundice) from birthVery high bilirubin levels in the bloodYellow coloring that does not improve without treatmentBrain damage from bilirubin buildup (kernicterus) if untreatedInvoluntary muscle movements or spasmsHearing lossDifficulty with coordination and balanceDelayed development in children who develop brain complicationsSeizures in severe casesAbnormal eye movements
Clinical phenotype terms (14)— hover any for plain English
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Neonatal
Begins at or shortly after birth (first 4 weeks)
FDA & Trial Timeline
1 eventGenethon — PHASE2
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Crigler-Najjar syndrome type 1.
1 clinical trialare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Crigler-Najjar syndrome type 1.
Community
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Caregiver Resources
NORD Caregiver Resources
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Mental Health Support
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Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What bilirubin level is safe for my child, and at what level should I seek emergency care?,How many hours of phototherapy does my child need each day, and what happens if we miss a session?,When should we start planning for a liver transplant, and what does that process involve?,Are there any clinical trials for gene therapy that my child might be eligible for?,How will we monitor for early signs of brain damage, and what tests are used?,What equipment do we need at home for phototherapy, and is it covered by insurance?,What specialists should be part of my child's care team, and how often should we have check-ups?
Common questions about Crigler-Najjar syndrome type 1
What is Crigler-Najjar syndrome type 1?
Crigler-Najjar syndrome type 1 (also called CN1 or Crigler-Najjar type I) is a very rare, serious liver disorder that a person is born with. It affects how the body processes bilirubin — a yellow substance made when red blood cells break down. Normally, the liver converts bilirubin into a form that can leave the body through bile. In Crigler-Najjar type 1, the liver enzyme responsible for this process (called UGT1A1) is completely absent or does not work at all. This causes bilirubin to build up to dangerous levels in the blood, a condition called hyperbilirubinemia. The most visible sign is
How is Crigler-Najjar syndrome type 1 inherited?
Crigler-Najjar syndrome type 1 follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Crigler-Najjar syndrome type 1 typically begin?
Typical onset of Crigler-Najjar syndrome type 1 is neonatal. Age of onset can vary across affected individuals.
Are there clinical trials for Crigler-Najjar syndrome type 1?
Yes — 1 recruiting clinical trial is currently listed for Crigler-Najjar syndrome type 1 on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Crigler-Najjar syndrome type 1?
11 specialists and care centers treating Crigler-Najjar syndrome type 1 are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.