Evaluation of the effects of terminating the diet in phenylketonuria

What is the Best Age to Discontinue the Low Phenylalanine Diet in Phenylketonuria ?

“…It is difficult to assess the effects of dietary discontinuation on &dquo;behavior.&dquo; In Solomons' et al 1 report, the behavior of five children improved after the diet was discontinued; however, E. H. and H. H. required Ritalin to control overactivity and distractibility, which developed off the diet. Since the diet was stopped near the time of school entry, the behavior demanded by the school may have necessitated medication for a child who already was overactive and distractible while still on the diet, but who had been no problem in his home environment.…”

Knowledge, compliance and serum phenylalanine concentrations in adolescents and adults with phenylketonuria and the effect of a patient‐focused educational resource

“…Hyperphenylalaninaemia was thought to have little impact on neurological development once the central nervous system was fully developed and dietary phenylalanine restriction was routinely stopped or relaxed in childhood (Behbehani et al. , 1986; Solomons et al. , 1996).…”

“…Phenylketonuria was traditionally viewed as a paediatric condition. Hyperphenylalaninaemia was thought to have little impact on neurological development once the central nervous system was fully developed and dietary phenylalanine restriction was routinely stopped or relaxed in childhood (Behbehani et al, 1986;Solomons et al, 1996). However, studies have demonstrated that discontinuation of dietary restriction at this age results in an impairment of cognitive development and intelligence quotient in adolescence and beyond (Smith et al, 1978Azen et al, 1996;Koch et al, 2002).…”

Treatment of classical phenylketonuria.

“…A number of authors have found little change in the IQ of children allowed ordinary food from early school age or even sooner (Horner, Streamer, Alejandrino, Reed, and Ibbot, 1962;Vandeman, 1963;Murphy, 1963;Solomons, Keleske, and Opitz, 1966;Hsia, 1966), but Centerwall, Centerwall, Acosta, and Chinnock (1961a) warned that a return of features such as irritability and clouding of affect could have an adverse effect on the child's progress even if the IQ did not decrease. Clayton, Moncrieff, Pampiglione, and Shepherd (1966) investigated this problem by observing the change in electroencephalographic patterns during phenylalanine loading tests.…”