What is the difference between Gilbert syndrome and Crigler-Najjar syndrome?
In the case of Gilbert syndrome two bases are inserted into the promoter of the gene. In Crigler-Najjar syndrome type I and II mutations lead to the exchange of amino acids, changes of the reading frame or to stop codons.
What is Crigler Najjar type 1?
Crigler Najjar syndrome , type 1 is an inherited disorder in which bilirubin, a substance made by the liver, cannot be broken down. This condition occurs when the enzyme that normally converts bilirubin into a form that can easily be removed from the body does not work correctly.
What is Crigler-Najjar syndrome type 2?
Crigler-Najjar syndrome type 2 (CN-2) is a rare disorder that causes elevated levels of bilirubin in the blood (hyperbilirubinemia). Bilirubin normally is made by the body when old red blood cells are broken down.
How does Crigler Najjar affect the circulatory system?
Crigler-Najjar Syndrome Diagnosis The acute stage of the disease may show an increased heart rate, poor circulation of fluids through the organs (perfusion), improper alignment of the eyes, weak gag reflex, and muscle spasms.
What causes Crigler-Najjar syndrome?
Crigler-Najjar syndrome is caused by absent or defective uridine diphosphate glucuronosyltransferase-1A1 (UGT1A1), the enzyme responsible for the conjugation of bilirubin.
How common is Crigler-Najjar syndrome?
Crigler-Najjar syndrome affects males and females in equal numbers. The incidence is estimated to be 1 in 750,000-1,000,000 people in the general population.
Is Crigler-Najjar fatal?
An episode of kernicterus can ultimately result in life-threatening brain damage. Although kernicterus usually develops early during infancy, in some cases, individuals with Crigler-Najjar syndrome type I may not develop kernicterus until later during childhood or in early adulthood.
How does hypothyroidism cause jaundice?
Congenital hypothyroidism: Hypothyroidism causes decreased rate of bilirubin conjugation, slows gut motility and impairs feeding, all contributing to jaundice.
What does Black liver mean?
Black liver is a common finding in Dubin-Johnson syndrome (DJS), which is caused by the lack of multidrug resistance-associated protein 2 (MRP2). Impaired excretion of epinephrine metabolites is believed to be a cause of black liver in DJS.
What is the most common cause of unconjugated hyperbilirubinemia?
Hyperbilirubinemia in children is usually unconjugated and most often caused by problems with red blood cell stability and survival or by defects in the bilirubin-conjugating enzyme, UGT. In contrast, disorders that result in conjugated hyperbilirubinemia are usually caused by intrinsic liver dysfunction.
Who were Crigler and Najjar?
Crigler-Najjar syndrome (CNS), named for the two physicians who first described the condition in 1952, John Crigler and Victor Najjar, is a rare, life-threatening inherited condition that affects the liver. CNS is characterized by a high level of a toxic substance called bilirubin in the blood (hyperbilirubinemia).
What kind of genetic testing is used for Crigler Najjar syndrome?
Molecular genetic testing can confirm a diagnosis of Crigler-Najjar syndrome. Molecular genetic testing can detect mutations in the UGT1A1 gene that are known to cause the disorder, but is available only as a diagnostic service at specialized laboratories. It is important to distinguish Crigler-Najjar syndrome type I and type II.
How many people are affected by Crigler Najjar syndrome?
Crigler-Najjar syndrome affects males and females in equal numbers. The incidence is estimated to be 1 in 750,000-1,000,000 people in the general population. Many researchers believe that the disorder often goes undiagnosed or misdiagnosed making it difficult to determine its true frequency in the general population.
How is phenobarbital used for Crigler Najjar syndrome?
The administration of phenobarbital, a barbiturate, reduces blood bilirubin levels individuals affected with Crigler-Najjar syndrome type II and Gilbert syndrome, but is ineffective for those with Crigler-Najjar syndrome type I. Therefore, failure to respond to this medication is an important indication for differential diagnostic purposes.
Why does Crigler Najjar syndrome cause high bilirubin levels?
Affected individuals cannot convert unconjugated bilirubin to the conjugated form because they lack a specific liver enzyme required to break down (metabolize) bilirubin. Since they cannot convert bilirubin, they develop abnormally high levels of unconjugated bilirubin in the blood (hyperbilirubinemia).
