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Crigler-Najjar syndrome

  • Definition

    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)


    Causes, incidence, and risk factors

    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 early-onset form of the disease. Arias syndrome (type 2) is a later-onset condition.

    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.