Tyrosinemias

**Definition:** A group of disorders which have in common elevations of tyrosine in the blood and urine secondary to an enzyme deficiency. Type I tyrosinemia features episodic weakness, self-mutilation, hepatic necrosis, renal tubular injury, and seizures and is caused by a deficiency of the enzyme fumarylacetoacetase. Type II tyrosinemia features INTELLECTUAL DISABILITY, painful corneal ulcers, and keratoses of the palms and plantar surfaces and is caused by a deficiency of the enzyme TYROSINE TRANSAMINASE. Type III tyrosinemia features INTELLECTUAL DISABILITY and is caused by a deficiency of the enzyme 4-HYDROXYPHENYLPYRUVATE DIOXYGENASE. (Menkes, Textbook of Child Neurology, 5th ed, pp42-3)

**Tree numbers:** - C10.228.140.163.100.875 - C16.320.565.100.880 - C16.320.565.189.875 - C18.452.132.100.875 - C18.452.648.100.880 - C18.452.648.189.875

**Synonyms:** - Tyrosinemia - Hereditary Tyrosinemias - Hypertyrosinemia - Tyrosinemias, Hereditary