DR Medhat MRCP

Crigler-Najjar Syndrome (CNS):
- (CNS) is a rare disorder affecting the metabolism of bilirubin, which results in high
levels of unconjugated bilirubin and often leads to brain damage in infants.
• Aetiology :
- Results from absent or severe decrease in activity of UDP Glucoronyl transferase.
• Types :
Type I : Absent enzyme activity
Type II ( Arias syndrome) : impaired enzyme activity.
- These two types, along with Gilbert's syndrome, Dubin-Johnson syndrome, and
Rotor syndrome, make up the five known hereditary defects in bilirubin metabolism.
- Unlike Gilbert's syndrome, only a few hundred cases of CNS are known.
- Type I is usually fatal while only type II can survive to adult life.
• Treatment :
Liver transplantation.
Dubin-Johnson syndrome :
- Is a benign autosomal recessive disorder resulting in conjugated hyperbilirubinemia
( Therefore present in urine).
• Aetiology :
- It is due to a defect in the canalicular multispecific organic anion transporter
(cMOAT) protein defective hepatic bilirubin excretion.
• Features:
• of conjugated bilirubin.
• NO elevation of liver enzymes (ALT, AST).
• Usually asymptomatic but may be diagnosed in early infancy based on laboratory
tests.
• Liver biopsy shows dark granules in the hepatocytes (thought to be due to melanin
deposition)
• Prognosis
- Is good, and treatment of this syndrome is usually unnecessary.
- Most patients are asymptomatic and have normal life spans.
91