Rare Disease Report

Rare Disease Spotlight: Tyrosinemia

NOVEMBER 06, 2015
RDR Staff
Tyrosinemia is a genetic inborn error of metabolism associated with severe liver disease in infancy if left untreated. There are 3 types of tyrosinemia—I, II, & III—with tyrosinemia type I being the most common of the rare conditions and the best understood.

Tyrosinemia type I is caused by a deficiency of the enzyme fumarylacetoacetate hydrolase (FAH). The absence of FAH leads to an accumulation of toxic metabolic products in various body tissues, which in turn results in progressive damage to the liver and kidneys. Tyrosinemia type I affects males and females in equal numbers.

Tyrosinemia type II is caused by a deficiency of the enzyme tyrosine aminotransferase. This form of the disorder can affect the eyes, skin, and mental development.

Tyrosinemia type III is caused by a deficiency of the enzyme 4-hydroxyphenylpyruvate dioxygenase.Symptoms may include intellectual disability, seizures, and intermittent ataxia.


Symptoms associated with tyrosinemia type I often vary greatly from case to case and may include:
  • Failure to gain weight
  • Fever
  • Diarrhea
  • Melena
  • Vomiting
  • Hepatomegaly
  • Jaundice
  • Lethargy
  • Cabbage-like odor
  • Irritability


  • Clinical evaluation
  • Blood and urine test: testing for increased succinylacetone concentration in the blood and urine.
  • Genetic testing
  • Prenatal diagnosis: possible through detection of succinylacetone in the amniotic fluid or measurement of fumarylacetoacetase in amniotic fluid cells.

 Medical Treatment

  • Nitisinone (Orfadin)- prevents the formation of maleylacetoacetic acid and fumarylacetoacetic acid, which have the potential to be converted to succinyl acetone, a toxin that damages the liver and kidneys. It is approved for the treatment of type I tyrosinemia
  • Diet of limited amounts of phenylalanine and tyrosine

 Surgical Treatment

  • Liver Transplant


The Network of Tyrosinemia Advocates (NOTA) offers resources and support to family members.
For more information, please visit http://notacares.org.

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