Directors of Photography:
Library and Archives Canada: 16mm.
"Phenylketonuria is a metabolic disorder, causing mental retardation because of the body's inability to convert phenylalanine to tyrosine. It therefore accumulates in the blood. High blood levels of phenylalanine inhibit the formation of serotonia, which plays an important role in brain metabolism. If diagnosed within the first twelve weeks of birth, a low phenylalanine diet will usually improve the condition of the patient."