Crigler-Najjar syndrome Health Article

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 is caused by an abnormal gene. The gene fails to make the enzyme that normally converts bilirubin into a form that can easily be removed from the body. 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 get 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.

Symptoms

• Confusion and changes in thinking
• Yellow skin (jaundice) and yellow in the whites of the eyes (icterus), which begin a few days after birth and get worse over time

Signs and tests

Tests used to evaluate liver function include:

• Conjugated (bound) bilirubin
• Liver biopsy, enzyme assay
• Total bilirubin level
• Unconjugated (unbound) bilirubin in blood

Treatment

Light treatment (phototherapy) is needed on a regular basis throughout life. In infants this is done using bilirubin lights (bili or 'blue' lights). Phototherapy becomes less successful after age 4, because thickened skin blocks the light.

Liver transplantation has been used successfully in some people with type 1 disease.

Blood transfusions may help control the amount of bilirubin in blood plasma. Calcium compounds are sometimes used to bind with and remove bilirubin in the gut.

The drug phenobarbitol is sometimes used to treat Arias syndrome (type 2).