Crigler-Najjar syndrome is a very rare inherited disorder in which bilirubin (a substance made by the liver) cannot be broken down.
Glucuronyl transferase deficiency (type I Crigler-Najjar); Arias syndrome (type II Crigler-Najjar)
Causes, incidence, and risk factors
Crigler-Najjar syndrome occurs when the
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.