Amino Acid Disorders

 

Phenylketonuria (PKU)

 

Definition

Phenylketonuria (PKU) is an autosomal recessive inherited disorder caused by the genetic mutation of the enzyme phenylalanine hydroxylase (PAH), which converts the essential amino acid phenylalanine into tyrosine. If its function is disrupted, an accumulation of toxic metabolic products occurs, which results in severe neurological damage if left untreated. For a child to inherit PKU, both parents must carry the faulty gene.

Diagnosis

The condition is diagnosed during newborn screening via the heel prick test taken 48-72 hours after birth.

Prevalence

1:10,000, babies born in Australia and New Zealand

Treatment

Treatment consists of a life-long strict low-protein diet. The level of protein intake from foods is based on the extent of the individual phenylalanine tolerance. In order to meet protein requirements, phenylalanine-free amino acid supplements need to be taken, which are also enriched with micronutrients in order to prevent malnutrition.Strict compliance with the diet and maintaining phenylalanine concentrations within the recommended reference ranges ensures normal development and life expectancy. When PKU is diagnosed early and treated with diet and supplement, children are able to reach their full potential.

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