Tyrosinemia
(TYR) - Type I, II & III
An Amino Acid Disorder
What is it?
Tyrosinemia is a hereditary inborn error of metabolism that causes severe liver disease in infancy. Affected persons commonly develop cirrhosis of the liver and will eventually require liver transplantation to survive.
Inheritance and Frequency
The gene defect for Tyrosinemia is an autosomal recessive genetic trait and is unknowingly passed down from generation to generation. This faulty gene usually emerges when two carriers have children together and pass it to their offspring. For each pregnancy of two such carriers, there is a 25% chance that the child will be born with the disease and a 50% chance that the child will be a carrier for the gene defect.
Studies show that one of every 100,000 live births will have Tyrosinemia.
Signs & Symptoms
The severest form of the disease causes symptoms within the first months of life, including poor weight gain, enlarged liver and spleen, swelling of the legs and increased tendency of bleeding.
Long Term Effects
Even with therapy, death frequently occurs within six to nine months of life for sufferers of the severe form. Children with the less severe form also suffer from enlargement of the liver and spleen, poor weight gain, vomiting and diarrhea.
Treatment
A diet low in phenylalanine, methionine and tyrosine is followed to keep affected children as healthy as possible for liver transplantation, which is the only proven treatment thus far for the disease.
History
Screening
Visit the What Does Your State Screen page to learn about your state's newborn screening program.
Supplemental Screening
If you live in a state that does not perform screening on its newborns for all detectable disorders, there are laboratories that will provide this screening for you no matter your state of residence. For more information about supplemental screening, visit our supplemental screening page. Also visit our frequently asked questions page for more information on newborn screening.
Other Sites of Reference
- OMIM - Tyrosinemia Type I
- OMIM - Tyrosinemia Type II
- OMIM - Tyrosinemia Type III
- GeneReviews - Tyrosinemia Type I
- Genetics Home Reference - Tyrosinemia
- National Organization for Rare Disorders - Tyrosinemia
- Tyrosinemia Family Website
- LowProtein.com Website
- Dietary Specialties - Low Protein Foods
Support Groups
National Coalition for PKU & Allied Disorders
P.O. Box 1244
Mansfield, MA 02048
Contact Person: Trish Mullaley
Phone: (877) 996-2723
E-mail: Write to National Coalition for PKU
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