Phenylketonuria

Phenylketonuria (PKU) is an autosomal recessive metabolic genetic disorder characterized by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase (PAH), rendering it nonfunctional. This enzyme is necessary to metabolize the amino acid phenylalanine (Phe) to the amino acid tyrosine. When PAH activity is reduced, phenylalanine accumulates and is converted into phenylpyruvate (also known as phenylketone), which is detected in the u... More

Phenylketonuria (PKU) is an autosomal recessive metabolic genetic disorder characterized by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase (PAH), rendering it nonfunctional. This enzyme is necessary to metabolize the amino acid phenylalanine (Phe) to the amino acid tyrosine. When PAH activity is reduced, phenylalanine accumulates and is converted into phenylpyruvate (also known as phenylketone), which is detected in the urine. Since its discovery, there have been many advances in its treatment. It can now be successfully managed by the patient under ongoing medical supervision to avoid the more serious side effects. If untreated it can cause problems with brain development, leading to progressive mental retardation, brain damage, and seizures. Early cases of PKU were treated with a low-phenylalanine diet. Recent research shows that diet alone may not prevent elevated phenylalanine levels. Optimal treatment involves maintaining blood Phe levels in a safe range...

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