Crigler-Najjar syndrome is an extremely rare genetic disorder characterized by the absence or severe deficiency of an enzyme called uridine diphosphate glucuronosyltransferase (UGT). This enzyme is responsible for the conjugation and elimination of bilirubin, a yellow pigment produced during the breakdown of red blood cells. Without sufficient UGT activity, bilirubin accumulates in the blood, leading to a condition known as hyperbilirubinemia.
The prevalence of Crigler-Najjar syndrome is estimated to be approximately 1 in every 1,000,000 to 1 in every 2,000,000 individuals worldwide. It is inherited in an autosomal recessive manner, meaning that both parents must carry a copy of the mutated gene for their child to be affected. The disorder is more commonly observed in individuals of certain ethnic backgrounds, such as those of European, Middle Eastern, or North African descent.
Crigler-Najjar syndrome is typically diagnosed in infancy or early childhood and can present with symptoms like jaundice, yellowing of the skin and eyes, and potential neurological complications if bilirubin levels become dangerously high. Treatment options include phototherapy, which involves exposure to specific wavelengths of light to help break down bilirubin, and in severe cases, liver transplantation may be necessary.