Tyrosinemia Type 1

• In Ontario, a heel prick is used to take a few drops of blood from each baby shortly after birth. The blood is tested for more than 25 treatable diseases, including tyrosinemia type 1.
• A screen positive result means that more tests are needed to know whether or not a baby has tyrosinemia. It does not mean that a baby has tyrosinemia. Babies identified at a young age through screening can be treated early to help prevent health problems.

Tyrosinemia type 1 is a rare, inherited (genetic) disease.

• Babies with tyrosinemia cannot break down tyrosine.
• Tyrosine is a building block of protein (also called an amino acid). It is found in many foods, including breast milk and infant formula.
• There are other rare forms of tyrosinemia (types II and III), which can sometimes be picked up by newborn screening.

• It is normal for parents and guardians to feel worried when their baby has a screen positive result. A ‘screen positive’ result does not mean that a baby has tyrosinemia. It means that there is a chance that the baby may have tyrosinemia.
• Follow-up testing is important to find out whether the baby truly has tyrosinemia.
• The baby’s health care provider or a health care provider at a newborn screening regional treatment centre will discuss the results with the baby’s family.
• Follow-up testing is arranged as soon as possible and involves blood and urine tests.
• It can take a few days to weeks to find out if a baby truly has tyrosinemia or not. This waiting period can be hard for families.

• Normal – the baby does not have tyrosinemia.
• Abnormal – the baby does have tyrosinemia and will need treatment. The family will be supported by a team of caring specialists.
• Inconclusive – more testing is required. The baby will be followed closely by a specialist to ensure that he/she receives optimal care.

While most babies with tyrosinemia appear normal at birth, early signs of the disease can include:

• poor weight gain (failure to thrive)
• feeding problems
• irritability
• extreme sleepiness (lethargy)
• yellowing of the whites of the eyes and skin (jaundice)
• fever
• vomiting
• diarrhea
• distinctive cabbage-like odor of the skin and urine

Early treatment helps to prevent serious and life-threatening health problems such as:

• developmental delay
• liver and kidney disease
• neurological problems

Treatment for tyrosinemia type 1 begins as early as possible and is life long.

• Treatment may include medication and a special diet that is low in protein (low in tyrosine).
• A team, including a metabolic doctor and a dietitian, cares for babies with tyrosinemia.
• Babies with tyrosinemia have their health and development checked regularly.
• Regular follow-up tests are used to monitor and adjust treatments.

• Children with tyrosinemia can be as healthy and intelligent as other children their age if tyrosine levels are well managed with diet and medication.
• If liver damage has already occurred, or if it occurs, a small number of children with tyrosinemia will require a liver transplant.