We report on the long-term follow-up of the first Italian patient with the tetrahydrobiopterin (BH4)-responsive type of phenylalanine hydroxylase deficiency (R243X/Y414C genotype). The patient was diagnosed by the newborn screening for phenylketonuria (PKU) and with a positive BH4 loading test. Introduction of BH4 (initially 10 and later 20 mg/kg/day) in addition to reduced low-phenylalanine di...

We describe an improved determination of phenylpyruvic acid (PPA) in blood plasma by ultraviolet spectrophotometric measurement of an enolborate complex. Sensitivity and recovery are well suited for accurate analy. sis in the range of 1.25 to 25 mg/liter. Sera from 10 fasting phenylketonuric subjects averaged 15.3 mg/liter (range, 4.8 to 25.0 mg/liter). A pronounced diurnal rhythm in plasma PPA...

Phenylalanine in serum and urine was determined by gas chromatography after it was converted, by action of nitrous acid, to the corresponding hydroxy acid, phenyllactic acid. After extraction with ether, the phenyllactic acid was derivatized with bis(trimethylsilyl) trifluoroacetamide under mild conditions, and the product was injected directly into the gas chromatograph. The precision of the m...

Phenylketonuria (PKU) results from a deficiency in phenylalanine hydroxylase, the enzyme catalyzing the conversion of phenylalanine (PHE) to tyrosine. Although this inborn error of metabolism was among the first in humans to be understood biochemically and genetically, little is known of the mechanism(s) involved in the pathology of PKU. We have combined mouse germline mutagenesis with screens ...

The hepatic phenylalanine hydroxylase system is complex, consisting of at least two enzymes and two non-protein cofactors. In classical phenylketonuria (PKU) the affect component has been shown to be the enzyme, phenylalanine hydroxylase. Recently, several variant forms of PKU have been identified which are due to deficiencies of two of the other components of the hydroxylase system, dihydropte...

INTRODUCTION In PKU there is little data comparing the prevalence of overweight and obesity in different countries. The aim of this cross sectional study was to evaluate prevalence data from different PKU treatment centres in Europe and Turkey. SUBJECTS AND METHODS In children, body mass index (BMI) and z scores and in adults BMI were calculated in 947 patients (783 children aged < 19 years; ...

BACKGROUND Hyperphenylalaninemia (HPA) and Phenylkeonuria (PKU) are metabolic errors caused by deficiency of phenylalanine hydroxylase enzyme, which results in increased level of phenylalanine. This increase is toxic to the growing brain. OBJECTIVES The purpose of this study was to compare the intellectual and developmental status in HPA and PKU children with normal population in national scr...

We describe a method for neonatal screening for biotinidase (EC 3.5.1.12) deficiency. Biotinidase activity is assessed colorimetrically from dried samples of whole blood spotted on the same filter papers as used in the neonatal screening for phenylketonuria. After the reaction, samples from normal infants are characteristically purple, whereas those from affected individuals are straw-colored. ...

Recent advances in genetics have transformed the mere possibilities of genetic testing and pre-implantation genetic diagnosis into clinical realities. Although undergraduate science professors are able to explicate the science behind these new technologies, they are not always ready to discuss the ethical and social impacts of these new practices. In order to introduce to our students the compl...

Prescriptive screening is defined as screening for diseases solely for the benefit of the individuals participating in the programme. Currently used screening programmes are examined at each stage of life-antenatal, postnatal, school age, adult life, and old age. It is concluded that most disorders for which screening can be confidently recommended for the benefit of the individual are those oc...