Lack of fetal effect on blood phenylalanine concentration in maternal phenylketonuria

1984 ◽  
Vol 104 (2) ◽  
pp. 245-247 ◽  
Author(s):  
Harvey L. Levy ◽  
Roger R. Lenke ◽  
Richard Koch
Keyword(s):  
Maternal Phenylketonuria ◽  
Phenylalanine Concentration ◽  
Blood Phenylalanine ◽  
Fetal Effect ◽  
Blood Phenylalanine Concentration

Does maternal knowledge impact blood phenylalanine concentration in Turkish children with phenylketonuria?

2008 ◽  
Vol 31 (S2) ◽  
pp. 213-217 ◽  
Author(s):  
H. Gokmen Ozel ◽  
T. Kucukkasap ◽  
G. Koksal ◽  
H. S. Kalkanoglu Sivri ◽  
A. Dursun ◽  
...  
Keyword(s):  
Maternal Knowledge ◽  
Phenylalanine Concentration ◽  
Turkish Children ◽  
Blood Phenylalanine ◽  
Blood Phenylalanine Concentration

scholarly journals Phenylalanine requirement in children with classical PKU determined by indicator amino acid oxidation

2002 ◽  
Vol 283 (6) ◽  
pp. E1249-E1256 ◽  
Author(s):  
Glenda Courtney-Martin ◽  
Rachelle Bross ◽  
Mahroukh Raffi ◽  
Joe T. R. Clarke ◽  
Ronald O. Ball ◽  
...  
Keyword(s):  
Amino Acid ◽  
Acid Oxidation ◽  
Phenylalanine Concentration ◽  
Two Phase ◽  
Amino Acid Oxidation ◽  
Blood Phenylalanine ◽  
Plasma Phenylalanine ◽  
Crossover Analysis ◽  
The Mean ◽  
The Difference

Dietary restriction of phenylalanine is the main treatment for phenylketonuria (PKU), and current estimates of requirements are based on plasma phenylalanine concentration and growth. The present study aimed to determine more precisely the phenylalanine requirements in patients with the disease by use of indicator amino acid oxidation, withl-[1-13C]lysine as the indicator. Breath13CO2 production (F13 co 2) was used as the end point. Finger-prick blood samples were also collected for measurement of phenylalanine to relate phenylalanine intake to blood phenylalanine levels. The mean phenylalanine requirement, estimated using a two-phase linear regression crossover analysis, was 14 mg · kg−1 · day−1, and the safe population intake (upper 95% confidence interval of the mean) was found to be 19.5 mg · kg−1 · day−1. A balance between phenylalanine intake and the difference between fed and fasted blood phenylalanine concentration was observed at an intake of 20 mg · kg−1 · day−1. The similarity between these two values (19.5 and 20 mg · kg−1 · day−1) suggests that the maximal phenylalanine intake for children with PKU should be no higher than 20 mg · kg−1 · day−1.

scholarly journals Receiver operating characteristic plots to evaluate Guthrie, Wallac, and Isolab phenylalanine kit performance for newborn phenylketonuria screening

1997 ◽  
Vol 43 (10) ◽  
pp. 1838-1842 ◽  
Author(s):  
Stephen T Wang ◽  
Sam Pizzolato ◽  
Helen P Demshar
Keyword(s):  
Clinical Outcome ◽  
Receiver Operating Characteristic ◽  
Likelihood Ratio ◽  
Operating Characteristic ◽  
Clinical Performance ◽  
Discriminatory Power ◽  
Phenylalanine Concentration ◽  
Cutoff Value ◽  
Blood Phenylalanine Concentration ◽  
Outcome Performance

Abstract We used ROC plots to evaluate the clinical performance of the Guthrie, Wallac, and Isolab assays for newborn phenylketonuria (PKU) screening and assessed the screening discriminatory power of these three assays by the area under the ROC plot, Youden’s J index, and the likelihood ratio. The use of these plots not only allows us to pinpoint the exact cutoff value in screening, but also provides a direct comparison of these three different assays in clinical outcome performance. The optimum cutoff for the newborn PKU screening is a blood phenylalanine concentration of 0.30, 0.27, and 0.18 mmol/L for the Guthrie, Wallac, and Isolab assays, respectively. We conclude that the Wallac and Isolab kits, like the Guthrie assay, are suitable for newborn PKU screening.

Neonatal Screening for Phenylketonuria: II. Age Dependence of Initial Phenylalanine in Infants With PKU

PEDIATRICS ◽  
1974 ◽  
Vol 53 (3) ◽  
pp. 353-357
Author(s):  
Neil A. Holtzman ◽  
E. David Mellits ◽  
Clayton H. Kallman
Keyword(s):  
The United States ◽  
Screening Tests ◽  
Health Departments ◽  
Initial Screening ◽  
Age Dependence ◽  
Phenylalanine Concentration ◽  
Initial Concentration ◽  
The Third ◽  
Blood Phenylalanine Concentration

The relationships between initial and follow-up blood phenylalanine concentration and between initial concentration and age were examined in infants with elevated screening tests. Data were provided by health departments and phenylketonuria (PKU) clinics. Among infants who attained levels of 20 mg/100 ml or more the following was observed: (1) one-fourth had only minimal elevations (to less than 10 mg/100 ml) on the initial screening test; (2) of those with minimal elevations 66% were screened on or before the third day of life; (3) most of those whose initial elevations were more than minimally elevated and most of those with minimal elevations who were screened early had follow-up phenylalanines of 30 mg/100 ml or more. In contrast, those with minimal initial elevations who were screened late were more likely to have follow-up phenylalanines between 20 and 30 mg/100 ml. They may represent a different form of PKU. The findings suggest that as long as most infants in the United States continue to be screened on or before 4 days of age, some infants with PKU will be missed.

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