Phenylketonuria (PKU)
Phenylketonuria (PKU) is a genetic condition that results in the impaired metabolism of the amino acid phenylalanine
Untreated PKU can lead to brain damage and mental retardation, as well as other serious medical problems
PKU is treated by enforcing a strict diet that restricts the intake of phenylalanine to prevent its build up within the body
- It is an autosomal recessive disease caused by a mutation to the gene encoding the enzyme phenylalanine hydroxylase
- Phenylalanine hydroxylase (PAH) normally converts excess phenylalanine within the body into tyrosine
- In people with PKU, the excess phenylalanine is instead converted into phenylpyruvate (also known as phenylketone)
- This results in a toxic build up of phenylketone in the blood and urine (hence phenylketonuria)
Untreated PKU can lead to brain damage and mental retardation, as well as other serious medical problems
- Infants with PKU are normal at birth because the mother is able to break down phenylalanine during pregnancy
- Diagnosis of PKU is made by a simple blood test for elevated phenylalanine levels shortly after birth
PKU is treated by enforcing a strict diet that restricts the intake of phenylalanine to prevent its build up within the body
- This low-protein diet should include certain types of fruits, grains, vegetables and special formula milk
- This diet should be supplemented with a medical formula that contains precise quantities of essential amino acids
- Patients who are diagnosed early and maintain this strict diet can have a normal life span without damaging symptoms
Metabolism of Phenylalanine – Healthy vs PKU