Crigler-Najjar syndrome

Alternative names:

glucuronyl transferase deficiency (type I)

Definition:

An inherited disorder of bilirubin metabolism in which bilirubin cannot be changed into its water-soluble form, bilirubin glucuronide. This is caused by an enzyme imbalance in the liver.

Causes, incidence, and risk factors:

Crigler-Najjar syndrome is inherited as an autosomal recessive trait. Parents who are carriers of this condition have about half the normal enzyme activity of an unaffected adult. Infants who inherit the trait from both parents (this is called homozygous inheritance) develop severe jaundice (hyperbilirubinemia) beginning a few days after birth. If these infants are not treated, they may develop kernicterus.

In infants who have inherited an affected gene from each of the parents, the jaundice will persist into adult life and require daily treatment. The constantly elevated levels of bilirubin eventually produce an adult form of kernicterus despite daily treatment.