How is Crigler-Najjar syndrome diagnosed?

Updated: May 21, 2019
  • Author: Hisham Nazer, MBBCh, FRCP, DTM&H; Chief Editor: BS Anand, MD  more...
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Although no simple, widely available clinical test is available to confirm the diagnosis of Crigler-Najjar syndrome, unconjugated hyperbilirubinemia in the presence of normal liver function test findings is characteristic of the disease.

Direct bilirubin is less than 15% of the total serum bilirubin in Crigler-Najjar syndrome. High-performance liquid chromatography analysis of duodenal bile reveals that, in Crigler-Najjar syndrome type 1, negligible bilirubin diglucuronides or monoglucuronides are present; in the type 2 syndrome, these conjugates are present but in low concentrations. DNA analysis can be very helpful in establishing the correct diagnosis.

Persistent unconjugated hyperbilirubinemia levels of more than 20 mg/dL after the first week of life in the absence of liver disease or hemolysis strongly suggests UGT deficiency.

Findings on abdominal imaging studies, such as plain radiography, computed tomography (CT) scanning, and ultrasonography, are normal in Crigler-Najjar syndrome.

Definitive diagnosis of Crigler-Najjar syndrome requires high-performance liquid chromatography of bile or a tissue enzyme assay of a liver biopsy sample.

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