BACKGROUND Metabolic control in phenylketonuria (PKU) may be influenced by parental ability because dietary treatment involves complex food choices. This is an observational study to compare maternal carer (MC) knowledge and parental education with phenylalanine concentrations in children with PKU. METHODS Children (n = 46; 26 boys) aged 1-10 years (median age 6 years) on dietary treatment we...

UNLABELLED In phenylketonuria, knowledge about the relation between behavior and plasma phenylalanine is scarce. The aim of this study was to determine whether high phenylalanine is associated with disturbed behavior noticed by the patient and or close environment (parents or partners). 48 early treated PKU patients (median age 8.5, range 0-35 years) participated (median phenylalanine concentra...

The flooding dose method, which is used to measure tissue protein synthesis, assumes equilibration of the isotopic labeling between the aminoacyl-tRNA pool and the tissue and blood free amino acid pools. However, this has not been verified for a phenylalanine tracer in an in vivo study. We determined the specific radioactivity of [3H]phenylalanine in the aminoacyl-tRNA and the tissue and blood ...

The injection of neonatal mice with phenylalanine resulted in a rapid decrease in brain polyribosomes and a concomitant increase in monomeric ribosomes. Animals of 1-16 days of age were equally affected by phenylalanine, although the brain polyribosomes of 60-day-old mice were relatively resistant to the effects of phenylalanine. The population of free polyribosomes appeared to be more sensitiv...

Indirect measurements have previously suggested that patients with classical phenylketonuria (PKU) do not convert significant amounts of phenylalanine to tyrosine. Low-dose continuous infusion techniques employing [2H5]phenylalanine and [2H2]tyrosine were used to quantitate in vivo phenylalanine hydroxylation in 10 subjects with classical phenylketonuria, 2 with hyperphenylalaninemia (HPA), and...

OBJECTIVE To analyse the association in newborns between blood levels of phenylalanine and feeding method and gestational age. STUDY DESIGN This observational, cross-sectional study included a sample of 11,829 infants between 2008 and 2013 in a Spanish region. Data were recorded on phenylalanine values, feeding method [breast, formula, mixed (breast plus formula), or partial or fully intraven...

Quantitative determination of plasma phenylalanine (Phe) is essential for the diagnosis of phenylketonuria (PKU) and the control of dietary therapy of PKU patients. We have adapted a spectrophotometric method (Clin Chim Acta 1991;201:95-8) based on phenylalanine dehydrogenase (EC 1.4.1.-) for rapid and accurate determinations of Phe with the Cobas Fara II centrifugal analyzer. The method is bas...

Oral administration of sapropterin hydrochloride, recently approved for use by the US Food and Drug Administration and the European Commission, is a novel approach for the treatment of phenylketonuria (PKU), one of the most common inborn errors of metabolism. PKU is caused by an inherited deficiency of the enzyme phenylalanine hydroxylase (PAH), and the pathophysiology of the disorder is relate...

Phenylketonuria is a metabolic disease caused by phenylalanine hydroxylase deficiency. Treatment is based on a strict natural protein-restricted diet that is associated with the risk of malnutrition and severe psychosocial burden. Oral administration of tetrahydrobiopterin can increase residual enzyme activity, but most patients with severe clinical phenotypes are nonresponders. We performed l...

We focused on the participation of GAP1, BAP2, and AGP1 in L-phenylalanine transport in yeast. In order to study the physiological functions of GAP1, BAP2, and AGP1 in L-phenylalanine transport, we examined the kinetics, substrate specificity, and regulation of these systems, employing isogenic haploid strains with the respective genes disrupted individually and in combination. During the chara...