Tyrosinemia Type 3: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Tyrosinemia Type 3?
A primary care doctor often manages day to day care and watches growth and development. Most patients also see a metabolic specialist, a doctor who treats problems with how the body breaks down food. A neurologist may help if there are seizures or balance problems. A dietitian helps with the diet.
What it is
Tyrosinemia type 3 is a rare inherited condition passed down through genes. People with it lack enough of an enzyme called 4-hydroxyphenylpyruvate dioxygenase, which helps break down a protein building block called tyrosine. Without it, tyrosine and related substances can build up in the blood. Over time, these can harm nerve cells. Some people with the condition have few or no symptoms.
Symptoms
The most common problems affect the brain and nervous system. These include learning problems (called intellectual disability), seizures, and periods of poor balance and coordination, called ataxia. Unlike the other types of tyrosinemia, type 3 does not cause liver problems. Symptoms vary from person to person.
Causes and who gets it
Tyrosinemia type 3 is caused by changes in a gene called HPD. A child must inherit one changed copy from each parent; parents carrying only one copy usually have no symptoms. This is the rarest of the three types, and only a few cases have been reported.
How doctors diagnose it
Doctors often first notice high tyrosine on a blood test, and newborn screening may flag the condition in some babies. Urine tests can check for acids that build up when the body cannot break down tyrosine. Genetic testing for HPD changes confirms the diagnosis.
Treatment
Treatment focuses on lowering tyrosine in the blood. The main approach is a low protein diet that limits tyrosine and another building block called phenylalanine. A dietitian helps families plan meals, and doctors may prescribe a medical formula that gives protein without these building blocks. Many people who start the diet early stay well, but results differ from person to person.
When to see a doctor
Talk to a doctor if a child has seizures, trouble with balance, learning problems, or developmental delays. Any child with a positive newborn screening result for high tyrosine needs prompt follow up testing.
How a direct primary care or concierge doctor fits in
A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed. A direct primary care doctor is paid a flat monthly fee instead of insurance billing. A concierge doctor works similarly but usually charges more and often bills insurance too. Either type can handle routine monitoring, order lab tests, and coordinate specialist care. Because tyrosinemia type 3 is rare and complex, they would refer the patient to a metabolic specialist while staying involved in overall care.
Common questions
Is tyrosinemia type 3 the same as other types of tyrosinemia?
No. There are three main types, and each one involves a different missing enzyme. Type 2 causes eye and skin problems, while type 3 does not. Type 3 is the rarest and mainly affects the nervous system.
Can tyrosinemia type 3 be cured?
There is no cure. A special diet can lower tyrosine levels and may prevent or reduce some problems. Results differ from person to person.
How is it different from tyrosinemia type 1?
Type 1 affects the liver and kidneys and can cause serious liver disease. Type 3 does not cause liver problems and mainly affects the nervous system.
Should siblings be tested?
Because the condition is inherited, brothers and sisters of a child with tyrosinemia type 3 could also have it. Parents can ask a doctor or a genetic counselor about testing for other children.
Sources
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
