Australian Society for Inborn Errors of Metabolism. Apolipoprotein B gene polymorphism and plasma lipid levels in phenylketonuric children. The role of the blood-brain barrier in the aetiology of permanent brain dysfunction in hyperphenylalaninaemia. The structural basis of phenylketonuria. Structural components of PAH. The discovery of phenylketonuria: Serum lipid concentrations in subjects with phenylketonuria and their families.

Am J Dis Child. Phenylketonuria in a low incidence population: However, the effect of PAH mutations on the clinical phenotype is variable. PAH catalyses the stereospecific hydroxylation of l -Phe, the committed step in the degradation of this amino acid. Analysis of phenylalanine hydroxylase genotypes and hyperphenylalaninemia phenotypes using L-[l- 13 C]phenylalanine oxidation rates in vivo:

Incidence of PKU by population. J Inherit Metab Dis.

higher biology pku essay

Blau N, Burgard P. Higyer of phenylketonuria after liver transplantation in a child with cirrhosis. Phenylketonuria PKU is an autosomal recessive inborn error of phenylalanine Phe metabolism resulting from deficiency of phenylalanine hydroxylase PAH.

However, dietary treatment does not come without challenges such as: A better understanding of the biochemistry, genetics and molecular basis of PKU, as well as the need for improved treatment options, has led to the development of new therapeutic strategies. Differential diagnosis of PKU from the disorders of synthesis or recycling of BH 4 may involve various testing regimes including BH 4 loading tests, measurement of urine and plasma pterin metabolites and neurotransmitter metabolites as well as blood spot dihydropteridine reductase measurement.

While much work remains to be done, the low cholesterol concentrations in PKU may have broader implications to both the pathophysiology of PKU and the development of cardiovascular disease CVD. As with many other metabolites, Phe concentrations are regulated to a steady state level with dynamic input and runout flux. Biochemistry of PKU Phe exists as d and l enantiomers, and l -Phe is an essential amino acid required for protein synthesis in humans.

  CASE STUDY AEROCOMP

A simple phenylalanine method for detecting phenylketonuria in large populations of newborn infants. Protein intake and requirements with reference to diet and health. Erlandsen H, Stevens RC. Structural components of PAH. Shama Bhat C, Ramasarma T.

higher biology pku essay

The human PAH gene Figure 5 is located on chromosome 12q American Academy of Pediatrics: PAH can be divided into a number of functional domains Figure 3Figure 4. Complete and persistent phenotypic correction of phenylketonuria in mice by site-specific genome integration of murine phenylalanine hydroxylase cDNA.

Phenylketonuria: An Inborn Error of Phenylalanine Metabolism

A model of human phenylalanine metabolism in normal subjects and in phenylketonuric patients. In older children, protein intake is calculated each day, whereby a child is allocated a certain number of grams or units of daily protein, depending upon longitudinal plasma Phe concentrations. Dietary Restriction A low Phe diet is used for treatment with, initially, the small amounts of Phe coming from breast milk or commercial infant formula considered sufficient intake in babies.

Requests to do so should be addressed to the Editor. Mutations can either be neutral with respect to phenotype, or pathogenic due to their disruption to enzyme structure and function.

  ARE BTECS ALL COURSEWORK

Phenylketonuria: An Inborn Error of Phenylalanine Metabolism

Other trials involving the use of recombinant retroviral vectors have been abandoned following the observation that these vectors may induce leukaemia-like disorders. Mr Robin Williams e-mail: Learning and behavioural difficulties but not microcephaly in three brothers resulting from undiagnosed maternal phenylketonuria.

First, it drives the endogenous production of the non-essential amino acid Tyr. An exceptional Albanian family with seven children presenting with dysmorphic features and mental retardation: Emerging PKU Therapies Although dietary restriction of Phe is the cornerstone of treatment for PKU, the practicalities of following the strict diet have led to trials of additional therapies.

However, despite the intensive study, the mechanism by which the aberrant Phe metabolism leads to intellectual impairment is yet to be explained. Phe exists as d and l enantiomers, and l -Phe is an essential amino acid required for protein synthesis in humans. Open in a separate window. Analysis of phenylalanine hydroxylase genotypes and hyperphenylalaninemia phenotypes using L-[l- 13 C]phenylalanine oxidation rates in vivo:

higher biology pku essay