Crigler Najjar Syndrome

National Organization for Rare Disorders, Inc.

Skip to the navigation

It is possible that the main title of the report Crigler Najjar Syndrome is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Crigler-Najjar syndrome is a rare genetic disorder characterized by an inability to properly convert and clear bilirubin from the body. Bilirubin is an orange-yellow bile pigment that is mainly a byproduct of the natural breakdown (degeneration) of old or worn out red blood cells (hemolysis). Normally, bilirubin created in this process is converted from an unconjugated form to a form that can be dissolved in water and excreted from the body (called conjugated bilirubin). Affected individuals cannot convert unconjugated bilirubin to the conjugated form because they lack a specific liver enzyme required to break down (metabolize) bilirubin. Since they cannot convert bilirubin, they develop abnormally high levels of unconjugated bilirubin in the blood (hyperbilirubinemia).

The hallmark finding of Crigler-Najjar syndrome is a persistent yellowing of the skin, mucous membranes and whites of the eyes (jaundice). There are two forms of this disorder: Crigler-Najjar syndrome type I, characterized by a nearly complete lack of enzyme activity and severe, even life-threatening symptoms; and Crigler-Najjar syndrome type II, characterized by partial enzyme activity and milder symptoms. Both forms are inherited as autosomal recessive traits and are caused by errors or disruptions (mutations) of the UGT1A1 gene.

Crigler-Najjar syndrome was first recognized in six infants of three couples who were blood relatives (consanguineous). These cases were reported in the medical literature in 1952 by Drs. Crigler and Najjar. In 1962, Dr. Arias reported a milder version of this disorder, which is now termed Crigler-Najjar syndrome type II.

Supporting Organizations

American Liver Foundation

39 Broadway, Suite 2700
New York, NY 10006
Fax: (212)483-8179
Tel: (800)465-4837

CLIMB (Children Living with Inherited Metabolic Diseases)

Climb Building
176 Nantwich Road
Crewe, CW2 6BG
United Kingdom
Tel: 4408452412173
Fax: 4408452412174

Children's Liver Disease Foundation

36 Great Charles Street
Birmingham, B3 3JY
United Kingdom
Tel: 1212123839
Fax: 1212124300

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311

Parents of Infants and Children with Kernicterus (P.I.C.K.)

P.O. Box 4482
Olathe, KS 66063
Tel: (312)274-9695

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  8/2/2016
Copyright  2016 National Organization for Rare Disorders, Inc.