Crigler-Najjar Syndrome

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Summary 1) First Aid for the Basic Sciences: Organ Systems by Tao Le

Crigler-Najjar Syndrome is a rare genetic syndrome (autosomal recessive) which is caused by a complete lack of hepatic glneuronyl transferase, the enzyme responsible for conjugation of indirect to direct bilirubin. On gross inspection, the liver appears normal.

Pathophysiology 2) Pathologystudent.com

Síndrome de Gilbert, Crigler-Najjar

There are actually two types of Crigler-Najjar, and boy are they different clinically. Type I CN is a super rare, autosomal recessive disorder in which patients have no UGT1A1 activity. UGT1A1 is a liver enzyme that participates in bilirubin processing (it conjugates bilirubin with one or two molecules of glucuronic acid, if you must know). The bile is colorless, with only trace amounts of unconjugated bilirubin. So the unconjugated bilirubin backs up into the blood, producing severe jaundice and icterus. The liver, by the way, looks totally normal under the microscope. Type 1 CN is fatal in the neonatal period unless the baby gets a liver transplant.

Type II CN is an autosomal dominant disorder in which patients have some UGT1A1 activity,  but it’s decreased (the enzyme is only capable of forming monoglucuronidated bilirubin). The  disorder is not fatal; in fact, the major consequence is simply really really yellow skin.

Causes 3) First Aid for the Basic Sciences: Organ Systems by Tao Le

  • Complete lack of hepatic glneuronyl transferase, the enzyme responsible for conjugation of indirect to direct bilirubin

Symptoms 4) First Aid for the Basic Sciences: Organ Systems by Tao Le

  • Jaundice at birth 
  • Kernicterus (bilirubin encephalopathy)

Crigler-Najjar Syndrome

Diagnosis 5) First Aid for the Basic Sciences: Organ Systems by Tao Le

  • Laboratory findings – Severely elevated serum indirect bilirubin (> 30 times normal values)

Treatment 6) Healthline.com

  • Phototherapy – prevents or treats yellowing of the skin
  • Blood Transfusion – In serious cases, a blood transfusion may be necessary to remove excess bilirubin from your bloodstream.
  • Liver Transplant  done when other measures fail
  • Phenobarbital – treat the symptoms of CNS

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