Crigler Najjar Syndrome Type 2 and Type 1: Symptoms, Causes, Diagnosis and Treatment

What is Crigler Najjar Syndrome?

Crigler Najjar Syndrome is a very rare congenital disorder of bilirubin metabolism. There are two types: Crigler Najjar Syndrome Type 1 and Type 2. There is defective activity of Uridine diphospho glucoronosyl transferase (UDP Transferase) and of greater severity than Gilberts Syndrome.

Types of Crigler Najjar Syndrome

There are two types of Crigler Najjar Syndrome: Type 1 and 2.

Crigler Najjar Syndrome Type 1

This is the most severe type because of absolute deficiency of the UDP Glucoronosyltransferase that results in the baby developing Kernicterus (brain damage due to elevated bilirubin levels) with death occurring within 18 months after birth unless a liver transplant is done; hence any adult diagnosed with Crigler Najjar Syndrome is type 2.

Crigler Najjar Syndrome type 1 has an Autosomal recessive pattern of inheritance. The liver is unable to synthesize a functional enzyme; the morphology of the liver appears normal when seen under a light microscope and electron microscope.

Crigler Najjar Syndrome Type 2 (Arias syndrome)

This is the mild form because of partial deficiency of UDP Glucoronosyltransferase that is not fatal as type 1. However, Type 2 Crigler Najjar Syndrome results in life long development of unconjugated hyperbilirubinemia except when a liver transplant is done. The mode of inheritance in type is autosomal dominant.

Crigler Najjar Syndrome Symptoms

  1. Jaundice occurring in the eyes (yellowish eyes) and also yellow skin

Crigler Najjar Syndrome Diagnosis

There is severe jaundice occurring in the first few days of life and persisting. The plasmas bilirubin level is elevated above 20 mg/dL. Definitive diagnosis is made by demonstration of deficiency of the enzyme by performing a liver biopsy after 3 months of age.

Crigler Najjar Syndrome Type 2 Treatment

  1. Since babies with type 1 cannot survive, we will discuss the treatment for type 2. The residual UDP Transferase enzyme activity of type 2 can be increased by use of the drug: Phenobarbital (which increases enzyme activity by induction), this causes a reduction of the unconjugated bilirubin and hence a subsequent reduction of Jaundice.
  2. Another form of treatment is use of phototherapy by using ultraviolet light.
  3. Severe cases can be treated by plasmapheresis
  4. A permanent form of treatment for Crigler Najjar Syndrome type 2 is liver transplant.

Differences between type 1 and type 2 of Crigler Najjar Syndrome

  1. Type 1 is not compatible with life whereas type is compatible
  2. Type 1 is autosomal recessive while type 2 is autosomal dominant
  3. Type 2 is also known as Arias syndrome

Similarities of type 1 and 2 Crigler Najjar Syndrome

  1. Both affect autosomes
  2. Both can be treated by liver transplant

Crigler Najjar Syndrome Prognosis

Prognosis for type 1 is poor whereas type 2 is good

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