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Tyrosinemia

By

Matt Demczko

, MD, Sidney Kimmel Medical College of Thomas Jefferson University

Last full review/revision Apr 2020| Content last modified Apr 2020
Click here for the Professional Version
  • Tyrosinemia is caused by a lack of the enzyme needed to metabolize the amino acid tyrosine.

  • Symptoms include intellectual disability, liver and kidney disease, and body fluids that smell like boiled cabbage.

  • The diagnosis is based on a blood test.

  • A special diet and sometimes drugs may help some children.

Amino acids Proteins Carbohydrates, proteins, and fats supply 90% of the dry weight of the diet and 100% of its energy. All three provide energy (measured in calories), but the amount of energy in 1 gram (1/28 ounce)... read more are the building blocks of proteins and have many functions in the body. Children with tyrosinemia are unable to completely break down (metabolize) the amino acid tyrosine. By-products of this amino acid build up, causing a variety of symptoms. These by-products also cause body fluids, such as urine and sweat, to smell like boiled cabbage.

There are two main types of tyrosinemia and a third, uncommon form:

  • Type I

  • Type II

  • Type III (rare)

Type I tyrosinemia

Type I tyrosinemia is most common among children of French-Canadian or Scandinavian descent.

Newborns may have liver failure. Older infants and children have dysfunction of the liver, kidneys, and nerves, resulting in irritability, rickets Hypophosphatemic Rickets Hypophosphatemic rickets is a disorder in which the bones become painfully soft and bend easily because the blood contains low levels of the electrolyte phosphate. (See also Introduction to... read more , or even liver failure and death.

Every state in the United States requires all newborns be screened for type I tyrosinemia with a blood test. To confirm the diagnosis, genetic testing or other tests of the blood and urine and a biopsy of the liver are done.

Restriction of the amino acids tyrosine and phenylalanine in the diet is recommended. A drug called nitisinone (also known as NTBC), which blocks production of toxic metabolites, may help children with type I tyrosinemia. Often, children with type I tyrosinemia require a liver transplant Liver Transplantation Liver transplantation is the surgical removal of a healthy liver or sometimes a part of a liver from a living person and then its transfer into a person whose liver no longer functions. (See... read more .

Type II tyrosinemia

Diagnosis of type II tyrosinemia is with a blood test. Other tests of the blood and urine and a biopsy of the liver may be done.

Treatment of type II tyrosinemia is by restricting tyrosine and phenylalanine in the diet.

Type III tyrosinemia

Diagnosis of type III tyrosinemia is with a newborn blood screening test. Urine and blood tests may also be done if the screening is abnormal.

Treatment of type III tyrosinemia is by restricting tyrosine and phenylalanine in the diet.

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