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Unlabelled: Treatment of hyperphenylalaninaemias due to phenylalanine hydroxylase deficiency with a low phenylalanine (Phe) diet is highly successful in preventing neurological impairment and mental retardation. There is consensus that, for an optimal outcome, treatment should start as early as possible, and that strict blood Phe level control is of primary importance during the first years of life, but for adolescent and adult patients international treatment recommendations show a great variability. A working party of the German Working Group for Metabolic Diseases has evaluated research results on IQ data, speech development, behavioural problems, educational progress, neuropsychological results, electroencephalography, magnetic resonance imaging, and clinical neurology. Based on the actual knowledge, recommendations were formulated with regard to indication of treatment, differential diagnosis, and Phe level control during different age periods. The development of the early-and-strictly-treated patient in middle and late adulthood still remains to be investigated. Therefore, the recommendations should be regarded as provisional and subject to future research. Efficient treatment of phenylketonuria has to go beyond recommendations for blood Phe level control and must include adequate dietary training, medical as well as psychological counselling of the patient and his family, and a protocol for monitoring outcome.Conclusions: Early-and-strictly-treated patients with phenylketonuria show an almost normal development. During the first 10 years treatment should aim at blood Phenylalanine levels between 40 and 240 micromol/L. After the age of 10, blood phenylalanine level control can be gradually relaxed. For reasons of possible unknown late sequelae, all patients should be followed up life-long. [ABSTRACT FROM AUTHOR]

Previously, we reported that Toxoplasma gondii (T. gondii)-seropositivity is associated with higher impulsive sensation seeking in younger men. As dopaminergic and serotonergic signaling regulate impulsivity, and as T. gondii directly and indirectly affects dopaminergic signaling and induces activation of the kynurenine pathway leading to the diversion of tryptophan from serotonin production, we investigated if dopamine and serotonin precursors or the tryptophan metabolite kynurenine interact with the T. gondii-impulsivity association. In 950 psychiatrically healthy participants, trait impulsivity scores were related to T. gondii IgG seropositivity. Interactions were also identified between categorized levels of phenylalanine (Phe), tyrosine (Tyr), Phe:Tyr ratio, kynurenine (Kyn), tryptophan (Trp) and Kyn:Trp ratio, and age and gender. Only younger T. gondii-positive men with a high Phe:Tyr ratio, were found to have significantly higher impulsivity scores. There were no significant associations in other demographic groups, including women and older men. No significant effects or interactions were identified for Phe, Tyr, Kyn, Trp, or Kyn:Trp ratio. Phe:Tyr ratio, therefore, may play a moderating role in the association between T. gondii seropositivity and impulsivity in younger men. These results could potentially lead to individualized approaches to reduce impulsivity, based on combined demographic, biochemical and serological factors., (Published by Elsevier B.V.)