Q. What is Phenylketonuria?

The essential amino acid phenylketonuria is utilized for tissue protein synthesis and hydroxylated to form tyrosine. The hydroxylation reaction requires phenylalanine hydroxylase. Phenylketonuria (PKU) is a group of inherited disorders of phenylalanine metabolism caused by impaired phenylulanine hydroxylase activity. PKU cannot break down phenylalanine into another amino acid, tyrosine. Phenylalanine then builds up in the bloodstream and causes brain damage.

Phenylketonuria, commonly referred to as PKU, occurs at the age of 3 to 6 months and is characterized by developmental delay, microcephaly (abnormally small head), abnormal electro-encephalogram, eczema, musty odour and hyper activity. Lf untreated before three weeks of age, the metabolic imbalance produces irreversible mental retardation. The defect in metabolism in classic PKU is associated with less than 2% activity of normal phenylalanine hydroxylase.