National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Crigler Najjar syndrome, type 1



Other Names:
Crigler-Najjar syndrome, type I
Categories:

Crigler Najjar syndrome, type 1 is an inherited disorder in which bilirubin, a substance made by the liver, cannot be broken down. This condition occurs when the enzyme that normally converts bilirubin into a form that can easily be removed from the body does not work correctly. Without this enzyme, bilirubin can build up in the body and lead to jaundice and damage to the brain, muscles, and nerves.[1] Crigler Najjar syndrome, type 1 is caused by mutations in the UGT1A1 gene. The condition is inherited in an autosomal recessive manner.[2] Treatment relies on regular phototherapy throughout life. Blood transfusions and calcium compounds have also been used. Liver transplantation may be considered in some individuals.[1]  
Last updated: 2/8/2011

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
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HPO ID
80%-99% of people have these symptoms
Biliary tract abnormality 0001080
Infantile muscular hypotonia
Decreased muscle tone in infant
0008947
Kernicterus 0001343
Neonatal hyperbilirubinemia 0003265
Prolonged neonatal jaundice
Prolonged yellowing of skin in newborn
0006579
Unconjugated hyperbilirubinemia 0008282
5%-29% of people have these symptoms
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay
[ more ]
0000750
Hearing impairment
Deafness
Hearing defect
[ more ]
0000365
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ]
0001249
Memory impairment
Forgetfulness
Memory loss
Memory problems
Poor memory
[ more ]
0002354
Oculomotor nerve palsy 0012246
Seizure 0001250
Tremor 0001337
Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance 0000007
Encephalopathy 0001298
Jaundice
Yellow skin
Yellowing of the skin
[ more ]
0000952
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Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes disorders of excessive bilirubin production (hemolysis, infections). CNS2 can be excluded by the absence of GT activity and lack of response to phenobarbital treatment and by DNA analysis.
Visit the Orphanet disease page for more information.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Organizations Providing General Support


These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Crigler Najjar syndrome, type 1. This website is maintained by the National Library of Medicine.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Crigler Najjar syndrome, type 1. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles


Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.


  1. Haldeman-Englert C. Crigler-Najjar syndrome. MedlinePlus. 2010; http://www.nlm.nih.gov/medlineplus/ency/article/001127.htm.
  2. UGT1A1. Genetics Home Reference (GHR). 2011; http://ghr.nlm.nih.gov/gene/UGT1A1. Accessed 2/8/2011.