What is Tyrosinemia?

Tyrosinemia is a serious genetic disorder caused by the deficiency of one of the enzymes required for breaking down tyrosine. A person with tyronsinemia has an overabundance of the amino acid tyrosine in the body. Without medication, tyrosine in the body continues to accumulate in the tissues and organs, thereby creating serious health complications. There are three types of this genetic disorder, each with varying symptoms caused by deficiency of a specific enzyme within the body. Each type requires ongoing medical treatment.

Type I tyrosinemia is the most severe form of the genetic disorder and is caused by the absence of the enzyme fumarylacetoacetate hydrolase. People of French-Canadian ancestry experience a higher risk of suffering from this particular condition. Babies born in Finland and Norway are also at a higher risk.

The disorder is diagnosed in infants and is characterized by inability to gain weight, jaundice, diarrhea, vomiting, an odor reminiscent of cabbage, and frequent bleeding. This particular type of tyrosinemia can cause kidney and liver failure. It can affect the nervous system, causes cirrhosis of the liver before the age of six months, and can lead to liver cancer as well. Without treatment, babies can die before they reach the age of 12 months.

Type II tyrosinemia is another form of the disorder which is marked by a deficient quantity of the enzyme called tyrosine aminotransferase. Young children are diagnosed with the disorder that includes the following symptoms: light sensitivity, tearing of the eyes, skin lesions, eye pain, and redness in the eyes. Type II can even affect mental development.

Type III tyrosinemia is an extremely rare condition characterized by impaired coordination and balance, slow mental development, and seizures. This particular type is caused by insufficient amounts of the enzyme 4-hydroxyphenylpyruvate dioxygenase in the body. The gene defect for tyrosinemia is passed down throughout the generations. Both parents of a child with tyrosinemia act as a carrier for the genetic disorder, but neither parent will show signs or symptoms of this particular condition.

When a child is diagnosed with the condition, doctors prescribe a medication called NTBC that helps to reverse symptoms of the disorder and a diet that contains reduced amounts of methionine, tyrosine, and phenylalanine. This diet is prescribed in order to improve the health of the child until a liver transplant can be performed. Liver transplants are the sole permanent treatment for this particular genetic disorder.