Rare Disease Spotlight: Tyrosinemia

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:


 Medical Treatment

 Surgical Treatment


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