"Hypotyrosinemia" in phenylketonuria.

It has been postulated that the significant incidence of learning disabilities in well-treated patients with phenylketonuria (PKU) may be due, in part, to reduced production of neurotransmitters as a result of deficient tyrosine transport across the neuronal cell membrane. Hypotyrosinemia has been reported in treated and untreated PKU but virtually no data are available. We decided to examine this in our patient population and to compare it with the published norms, patient data from our hospital clinical biochemical laboratory database, and a group of normal children and adolescents in a private pediatric practice.

Intelligence patterns among children with high-functioning autism, phenylketonuria, and childhood head injury.

High-functioning children with autistic-spectrum disorder show the typical pattern of lower Comprehension relative to their own scores on Block Design. This profile is shared, almost exactly, by age- and IQ-matched children with poorer control PKU. Quite distinct profiles are shown by children with better control PKU, who show no difference between Block Design and Comprehension, and by children with head injury involving frontal lobe contusion, who show slightly better Comprehension that Block Design.

Randomised controlled trial of tyrosine supplementation on neuropsychological performance in phenylketonuria.

Objective: To test the efficacy of tyrosine supplementation, as an adjunct to dietary treatment, on neuropsychological test performance in individuals with phenylketonuria.

Design: A randomised controlled trial of tyrosine supplementation using a double blind crossover procedure with three four week phases.

Setting: The Hospital for Sick Children, Toronto.

Newborn phenylketonuria (PKU) Guthrie (BIA) screening and early hospital discharge.

Recent policies of early discharge of postpartum mothers and their infants has raised concerns of possible decreased sensitivity in Guthrie bacterial inhibition assay (BIA) phenylketonuria (PKU) screening resulting in missed cases. In order to assess the potential impact of early discharge from hospital on neonatal screening for PKU and its variants, we performed 18 standard BIA screening tests on 11 newborn infants with the disease. Blood spot samples were collected from 1 to 24 h after birth and were analyzed at the Ontario Ministry of Health newborn screening laboratory according to the routine screening protocol.

Vitamin B12 deficiency in adolescents and young adults with phenylketonuria.

Following several years absence from clinical follow up, an 18-year-old female on diet therapy for phenylketonuria presented with spastic paraparesis, tremor, disorientation, slurred speech, distractibility, deteriorating mental function and megaloblastic anaemia (Hb 64g/l mean corpuscular volume 121). Plasma phenylalanine levels were 100-600 mumol/l for the first 18 months of life but thereafter, because of serious psycho-social factors, > 1200 mumol/l. Her diet had strictly excluded all meats, eggs and dairy products but she had been ingesting her medical food (Lofenalac) only irregularly.