Phenylketonuria is a genetic disorder (autosomal recessive) in which the body lacks the enzyme required to break down the amino acid phenylalanine. Failure to break down phenylalanine leads to its, and related compounds, buildup, causing damage to the central nervous system. A strict diet begun at birth can help mitigate the negative consequences, namely mental retardation, hyperactivity, and motor control problems. Screening newborn infants for phenylketonuria is a standard medical practice.
Modified from the Diagnostic and Statistical Manual of the American Psychiatric Association, Fourth edition (► DSM-IV) and the NIH-NLM MedlinePlus Encyclopedia (online)
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