Crigler Najjar Syndrome

  • Crigler–Najjar syndrome is a rare inherited disorder affecting the metabolism of bilirubin due to Genetic deficiency ot total absence of UDPG(uridine diphosphate glucuronyl) transferase.
  • The disorder results in a form of nonhemolytic jaundice, which results in high levels of unconjugated bilirubin.
  • Conversion of bilirubin to a water-soluble form is essential for its elimination is achieved by glucuronic acid conjugation with bilirubin.
  • Bilirubin diglucuronide is a conjugated form of bilirubin formed in bilirubin metabolism
  • Bilirubin is primarily excreted in normal human bile as diglucuronide
  • The disorder is inherited in an autosomal recessive manner.
  • This syndrome is divided into types I and II.
  • This is a very rare disease and consanguinity increases the risk of this condition.
  • Intense jaundice appears in the first days of life and persists thereafter.
  • Type 1 is characterised by a serum bilirubin usually above 345 ┬Ámol/L [20 mg/dL] .
  • Bile is pale in type I .
  • Conjugated bilirubin as Diglucuronide is absent in bile. No UDP glucuronosyltransferase 1-A1 expression can be detected in the liver tissue

  • There is no response to treatment with phenobarbital.
  • Kernicterus may develop.
  • Bilirubin levels are generally below 345 ┬Ámol/L [20 mg/dL].
  • Some cases are only detected later in life.
  • Bile is pigmented.
  • There is a deficiency of Diglucuronide in the bile .
  • UGT1A1 is present at reduced but detectable levels.
  • Treatment with phenobarbital is effective.
  • Kernicterus is rare in type II.
Exam Question
  • Deficiency of Diglucuronide is present in Crigler-Najjar syndrome Type-II

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