Tyrosinemia

Tyrosinemia is a group of rare genetic disorders characterized by disruptions in the metabolic pathway of the amino acid tyrosine. This results in an accumulation of tyrosine and its by-products in the body, leading to a variety of health problems. There are three types of tyrosinemia, each with distinct symptoms and treatment options.

Types of Tyrosinemia

There are three types of tyrosinemia, each caused by the deficiency of a different enzyme involved in the metabolic pathway of tyrosine.

Tyrosinemia Type I

Tyrosinemia Type I is the most severe form of the disorder. It is caused by a deficiency of the enzyme fumarylacetoacetate hydrolase (FAH). Symptoms usually appear in the first few months of life and include failure to gain weight and grow at the expected rate (failure to thrive), diarrhea, vomiting, yellowing of the skin and whites of the eyes (jaundice), and a cabbage-like odor.

Tyrosinemia Type II

Tyrosinemia Type II, also known as Richner-Hanhart syndrome, is caused by a deficiency of the enzyme tyrosine aminotransferase (TAT). Symptoms can include painful skin lesions on the palms and soles, eye abnormalities, and intellectual disability.

Tyrosinemia Type III

Tyrosinemia Type III is the rarest form of the disorder and is caused by a deficiency of the enzyme 4-hydroxyphenylpyruvate dioxygenase (HPD). Symptoms can include intellectual disability, seizures, and periodic loss of balance and coordination (ataxia).

Diagnosis

Diagnosis of tyrosinemia is based on the presence of characteristic symptoms, a detailed patient history, a thorough clinical evaluation, and a variety of specialized tests. These tests can include blood and urine tests, genetic testing, and liver biopsy.

Treatment

Treatment of tyrosinemia is aimed at managing the symptoms and preventing complications. This can include a low-protein diet, medications, and in some cases, liver transplantation.

See Also

• Amino acid metabolism disorder
• Genetic disorder
• Metabolic disorder

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