[Behavior problems in phenylketonuria. Attempt at a biochemical interpretation based on a personal case and a review of the literature].

We have presented the case of a 7 year old retarded child with psychotic like behavioral troubles. Biological studies are compatible with typical phenylketonuria. Two times, a low phenylalanine diet was followed by an improvement of the behavioral troubles, and the interruption of the diet by a relapse of these troubles. Biologically, an hyposerotoninergy was recorded by the lowering of the 5 HIAA renewal in CSF after probenecid, partially corrected by the low phenylalanine diet. From this personal case and a review of the literature, the authors discuss the biochemical interpretation of the behavioral troubles in the light of the serotoninergic deficit.