Tyrosinemia is an inherited disorder that occurs when the amino acid tyrosine cannot be broken down due to an enzyme deficiency. The enzyme fumarylacetoacetate finishes breaking down tyrosine in the body. However, in people with tyrosinemia, there is not enough of this enzyme for tyrosine to be completely broken down. As a result, tyrosine accumulates, which can affect the liver, kidneys, and nervous system.
You may also hear tyrosinemia called FAH deficiency or hereditary tyrosinemia type I.
Common symptoms of tyrosinemia include:
These symptoms usually show up in the first months of a person’s life and will vary in severity.
Tyrosinemia is an autosomal recessive condition, meaning you have to inherit a changed gene from both parents to get the disease. The gene mutation that causes tyrosinemia affects the FAH gene, which makes the FAH protein that breaks tyrosine down.
If you inherit only one altered gene and one normal gene, you’re a carrier for the mutated FAH gene. Carriers usually do not have symptoms, but they can pass the altered gene on.
When two carrier parents have a child, there’s a 25% chance the child will inherit both altered genes and have the condition. Parents considering having children who know they have a family history of tyrosinemia may want to undergo genetic testing first.
The only risk factor for tyrosinemia is a family history of the disease.
If your doctor suspects you or your child have tyrosinemia, they will use a thorough physical exam, family medical history, and testing to make a definitive diagnosis. Genetic testing is a common way to make a definitive diagnosis.
Complications of tyrosinemia include liver disease, developmental delays, enlargement of the spleen, fluid accumulation in the abdomen, and even life-threatening illness. It’s essential to get diagnosed and treated promptly.
Treatment & Management
A combination of medication and low-protein diets are typically used to manage tyrosinemia effectively. Having a nutritionist as part of a comprehensive support team and getting blood tyrosine levels checked frequently are essential parts of maintaining a high quality of life. Liver transplantation is available if end-stage liver failure is reached.