Crigler-Najjar syndrome is a rare inherited disorder that prevents the liver from properly processing bilirubin, a yellow pigment produced when red blood cells break down. It is caused by a deficiency or absence of the enzyme UDP-glucuronosyltransferase, which converts toxic unconjugated bilirubin into a form the body can eliminate. The Bilirubin, Total test is the most important diagnostic test for Crigler-Najjar syndrome, as it reveals markedly elevated levels of unconjugated bilirubin in the blood.
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Crigler-Najjar syndrome is caused by genetic mutations in the UGT1A1 gene, which provides instructions for making the UDP-glucuronosyltransferase enzyme. This enzyme is essential for converting unconjugated bilirubin (a toxic, fat-soluble form) into conjugated bilirubin (a water-soluble form that can be eliminated through bile). When this enzyme is missing or severely reduced, unconjugated bilirubin accumulates in the bloodstream and tissues, causing severe jaundice and potentially dangerous neurological complications if levels become extremely high.
The Bilirubin, Total test is the most important diagnostic test for Crigler-Najjar syndrome because it measures both conjugated and unconjugated bilirubin levels in the blood. In Crigler-Najjar syndrome, you will see severely elevated total bilirubin with the majority being unconjugated bilirubin, often ranging from 20-50 mg/dL or higher compared to normal levels of less than 1.2 mg/dL. This distinctive pattern of extremely high unconjugated bilirubin with little to no conjugated bilirubin is the hallmark of this rare genetic disorder and distinguishes it from other causes of jaundice.
You should get tested if you or your newborn baby develops severe, persistent jaundice that appears within the first few days of life and does not respond to standard phototherapy treatment. Testing is also important if there is a family history of Crigler-Najjar syndrome or unexplained jaundice in infancy, or if you notice yellowing of the skin and eyes that worsens over time. Early diagnosis through bilirubin testing is critical because extremely high bilirubin levels can cause permanent brain damage, making prompt identification and management essential.
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What this means
Your total bilirubin is slightly elevated above the normal range. While mild elevations can be harmless (such as in Gilbert syndrome), it's worth monitoring as it may indicate your liver is under stress or not processing bilirubin efficiently. This could contribute to subtle symptoms like fatigue or occasional yellowing of the eyes.
Recommended actions
Limit or avoid alcohol consumption to reduce liver stress
Stay well-hydrated and eat a liver-friendly diet with plenty of vegetables and whole grains
Avoid prolonged fasting, which can temporarily raise bilirubin levels
Consider retesting in 4-6 weeks to see if levels normalize or remain elevated
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