What is Crigler-Najjar syndrome

Crigler-Najjar syndrome is a rare genetic disorder characterized by the absence or deficiency of an enzyme called uridine diphosphate glucuronosyltransferase (UGT). This enzyme is responsible for converting bilirubin, a yellow pigment produced during the breakdown of red blood cells, into a soluble form that can be excreted from the body.

In individuals with Crigler-Najjar syndrome, the lack of functional UGT enzyme leads to the accumulation of unconjugated bilirubin in the blood, resulting in a condition known as hyperbilirubinemia. This can cause yellowing of the skin and eyes (jaundice) and potentially lead to complications such as brain damage due to the toxic effects of high bilirubin levels.

Crigler-Najjar syndrome is classified into two types: type 1 and type 2. Type 1 is the more severe form, where there is a complete absence of UGT enzyme activity. It requires lifelong treatment with phototherapy (light therapy) and may necessitate liver transplantation. Type 2 is a milder form, where there is some residual UGT enzyme activity, and treatment may involve medications to help reduce bilirubin levels.

Due to its rarity, Crigler-Najjar syndrome often requires specialized medical care and ongoing management to prevent complications associated with high bilirubin levels.