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Crigler Najjar syndrome, type 2

Other Names for this Disease
  • Crigler-Najjar syndrome, type II
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Crigler Najjar syndrome, type 2 is caused by mutations in the UGT1A1 gene. The gene mutation causes the body to be unable to make adequate enzyme to convert bilirubin into a form that can easily be removed from the body. Without this enzyme, bilirubin can build up in the body and lead to extraordinarily yellow skin and eyes (jaundice).[1] This condition is less severe than the type 1 form, however the severity of type II can vary greatly. Almost all patients with Crigler Najjar syndrome, type 2 develop normally, but there is a risk for some neurologic damage from kernicterus (bilirubin accumulation in the brain). In general people with type 2 Crigler Najjar syndrome have serum bilirubin levels ranging from 20 to 45 mg/dL.[2] Phenobarbital treatment is the standard therapy for this condition and can often help to drastically reduce the bilirubin levels.
Last updated: 1/19/2011


  1. Crigler Najjar syndrome. MedlinePlus. Accessed 1/19/2011.
  2. Crigler Najjar syndrome, type II. Online Mendelian Inheritance in Man. Accessed 1/19/2011.
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  • Genetics Home Reference (GHR) contains information on Crigler Najjar syndrome, type 2. 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) is a federation of more than 130 nonprofit voluntary health organizations serving people with rare disorders. Click on the link to view information on this topic.

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  • Medscape Reference provides information on this topic. Click on the link to view this information. You may need to register to view the medical textbook, but registration is free.
  • The Online Mendelian Inheritance in Man (OMIM) is an 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 2. Click on the link to view a sample search on this topic.

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