Which syndrome is associated with severe jaundice in neonates due to congenital unconjugated hyperbilirubinemia?

Crigler-Najjar syndrome is characterized by severe jaundice in neonates due to congenital unconjugated hyperbilirubinemia. This syndrome results from a genetic defect in the enzyme UDP-glucuronosyltransferase, which is responsible for the conjugation of bilirubin in the liver. In neonates with Crigler-Najjar syndrome, this enzymatic deficiency leads to an accumulation of unconjugated bilirubin in the bloodstream, causing significant jaundice, which may present shortly after birth.

There are two types of Crigler-Najjar syndrome: type 1, which is more severe and often results in kernicterus and requires treatment such as exchange transfusions and phototherapy, and type 2, which is milder and may respond to phenobarbital in some cases. The high levels of unconjugated bilirubin are the hallmark of this condition, resulting in the severe jaundice observable in affected neonates.

In contrast, Gilbert's syndrome is characterized by mild unconjugated hyperbilirubinemia but usually not to the level that would cause severe jaundice in newborns. Dubin-Johnson syndrome and Rotor syndrome, on the other hand, involve conjugated hyperbilirubinemia