Evidence continues to accumulate supporting the value of phenylalanine-deficient diets in the early management of children with phenylketonuria. Because the brain seems particularly susceptible to damage in the first few months of life, early detection and treatment of the phenylketonuric child has been advocated.3,6 Among the problems requiring further study is the question of when dietary treatment can be stopped with reasonable assurance of safety from further damage.
Our purpose here is to report two patients treated from an early age who were allowed a full normal diet after three years of age. They were treated from ages 19 weeks and 4 weeks, and taken off treatment at ages 34 and 36 months, respectively. Their ages at last psychometric testing were 88 and 77 months. These two children were previously reported in brief by Armstrong, Low, and Bosma.2
The dietary program used was that outlined by Armstrong and