Phenylketonuria (PKU) is a rare, inherited metabolic disorder that is characterized by the inability of the body to utilize the essential amino acid, phenylalanine (Phe). Amino acids, usually obtained from the food we eat, are the building blocks for body proteins. PKU is caused by a deficiency of the liver produced enzyme phenylalanine hydroxylase (PAH).

This enzyme normally converts Phe to another amino acid, tyrosine. Without this enzyme, Phe accumulates in the blood and body tissues. Excess Phe is toxic to the central nervous system and causes the severe problems normally associated with PKU. When left untreated, PKU patients who consume too much Phe are at risk of severe neurological complications, including IQ loss, memory loss, concentration problems, mood disorders, and in some cases, severe mental retardation.

Damage done is irreversible so early detection is crucial. When treatment is begun early (within the first few weeks of life) and rigorously adhered to, affected children can expect normal development and a normal life span. PKU can be treated by a diet low in phenylalanine and high in tyrosine. While there is no cure, in recent years a few drug products have become available that can be used in limited cases to mitigate the effects of the disorder. Other therapies currently under investigation include an injectable form of PAH and gene therapy.



The Minnesota PKU Foundation is pooling our research energy with the National PKU Alliance (NPKUA).  The NPKUA is proud to announce that it has agreed to fund several research projects.  Information on the research that the NPKUA and Minnesota PKU Foundation are involved in can be found at the NPKUA website.

Genetics and PKU

Genes can sometimes contain mistakes so that the cell can't read them properly. We can call this a "non-working gene".

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Diagnosing PKU

All newborn babies in Minnesota are tested for PKU during the newborn screening test where a sample of blood is taken from a prick on the baby's heel.

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Living with PKU

PKU is a chronic condition that requires ongoing management and support of medical staff.

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