DEFINITION:  Crigler-Najjar syndrome is a genetic disease characterized by a persistent unconjugated hyperbilirubinemia (elevated bilirubin levels).
CAUSE: It is due to deficiency of the liver enzyme UGT1A1, which is necessary for bilirubin excretion
into the bile.
imageCLINICAL MANIFESTATION: Severe, persistent jaundice, a condition in which the skin and the whites of the eyes become yellow. This is due to excessive plasmatic levels of bilirubin (> 20 mg/dL in Crigler-Najjar type I patients). Whether untreated severe jaundice may result in brain damage (kernicterus).
GENETICS: The disease is inherited as an autosomal recessive trait, meaning that the gene involved is not on one of the sex chromosomes; it also means that in order for a person to have the disorder the genetic change must be present in both copies of the gene, one inherited from the mother and one from the father.
Crigler-Najjar syndrome is very rare, real incidence is unknown (approx. less than 1 case per 1,000,000 births).