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Crigler-Najjar syndrome


Crigler-Najjar syndrome is a very rare inherited disorder in which bilirubin (a substance made by the liver) cannot be broken down.

Alternative Names

Glucuronyl transferase deficiency (type I Crigler-Najjar); Arias syndrome (type II Crigler-Najjar)


Crigler-Najjar syndrome 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 (yellow discoloration of skin and eyes) and damage to the brain, muscles, and nerves.

Crigler-Najjar (type 1) is the form of the disease that starts early in life. Arias syndrome (type 2) starts later in life.

The syndrome runs in families (inherited). A child must receive a copy of the defective gene from both parents to develop the severe form of the condition. Parents who are carriers (with just one defective gene) have about half the enzyme activity of a normal adult, but do not have symptoms.


  • Confusion and changes in thinking
  • Yellow skin (jaundice) and yellow in the whites of the eyes (icterus), which begin a few days after birth and get worse over time

Exams and Tests

Tests of liver function include:

  • Conjugated (bound) bilirubin
  • Enzyme assay
  • Liver biopsy
  • Total bilirubin level
  • Unconjugated (unbound) bilirubin in blood


Light treatment (phototherapy) is needed throughout a person's life. In infants, this is done using bilirubin lights (bili or 'blue' lights). Phototherapy does not work as well after age 4, because thickened skin blocks the light.

A liver transplant can be done in some people with type 1 disease.

Blood transfusions may help control the amount of bilirubin in blood. Calcium compounds are sometimes used to remove bilirubin in the gut.

The drug phenobarbitol is sometimes used to treat Arias syndrome (type 2).

Outlook (Prognosis)

Milder forms of the disease (type 2) do not cause liver damage or changes in thinking during childhood. People who are affected with a mild form still have jaundice, but they have fewer symptoms and less organ damage.

Infants with the severe form of the disease (type 1) may continue to have jaundice into adulthood, and may need daily treatment. If left untreated, this severe form of the disease will lead to death in childhood.

People with this condition who reach adulthood will develop brain damage due to jaundice (kernicterus), even with regular treatment. The life expectancy for type 1 disease is 30 years.

Possible Complications

Possible complications include:

  • A form of brain damage caused by jaundice (kernicterus)
  • Chronic yellow skin/eyes

When to Contact a Medical Professional

Seek genetic counseling if you are planning to have children and have a family history of Crigler-Najjar.

Call your health care provider if you or your newborn infant has jaundice that does not go away.


Genetic counseling is recommended for people with a family history of Crigler-Najjar syndrome who want to have children. Blood tests can identify people who carry the gene.


Carey RG, Balistreri WF. Metabolic diseases of the liver. In: Kliegman RM, Stanton BF, St. Geme J, Schor N, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 349.

Review Date:9/11/2014
Reviewed By:Chad Haldeman-Englert, MD, FACMG, Wake Forest School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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Outcome Data

No data available for this condition/procedure.


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