| Optimized loading test to evaluate responsiveness to tetrahydrobiopterin (BH(4)) in Brazilian patients with phenylalanine hydroxylase deficiency. | |
| | |
MedLine Citation:
|
PMID: 22014474 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
|
INTRODUCTION: Recent studies showed that phenylalanine (Phe) plasma concentrations may decrease in some patients with hyperphenylalaninemia (HPA) due to phenylalanine hydroxylase (PAH) deficiency, after the administration of tetrahydrobiopterin (BH(4)). OBJECTIVE: To determine responsiveness to a single dose of BH(4) administered according to an innovative protocol using a combined Phe and BH(4) loading test in Brazilian phenylketonuria (PKU) patients. METHODS: Patient age should be ≥4years, and median Phe plasma concentration ≤600μmol/L when following dietary restrictions. Participants received a simple Phe loading test using 100mg/kg L-Phe (Test 1) and a combined Phe+BH(4) loading test using 100mg/kg L-Phe and 20mg/kg/BH(4) (Test 2). Blood samples were collected at baseline and 3, 11 and 27h after Phe ingestion (T0, T1, T2 and T3). Responsiveness was defined as: criterion A: plasma Phe reduction of ≥30% at T1 and T2 for Tests 1 and 2; criterion B: plasma Phe reduction of ≥30% at T1 and T3 for Tests 1 and 2; and criterion C: at least 30% difference of the areas under the Phe curve for Tests 1 and 2. RESULTS: Eighteen patients (median age 12yrs; 8 classical PKU; 10 mild PKU) participated in the study. Six patients (2 classical PKU; 4 mild PKU) were classified as responsive according to at least one of the criteria. Responsiveness was concordant when criteria A+B we compared with criterion C (kappa=0.557; p=0.017). Of the patients whose genotype was available (n=16), six had data about BH(4)-responsiveness genotypes described in the literature, which were in agreement with our findings. CONCLUSION: The comparison of simple Phe loading and combined Phe+BH(4) loading seems to be an optimal method to evaluate responsiveness to BH(4) in patients with good metabolic control. |
| | |
Authors:
|
Tatiéle Nalin; Ingrid Dalira Schweigert Perry; Angela Sitta; Carmen Regla Vargas; Maria Luiza Saraiva-Pereira; Roberto Giugliani; Nenad Blau; Ida Vanessa Doederlein Schwartz |
Related Documents
:
|
22071024 - Predictors of bone mineral density testing in patients at high risk of osteoporosis: se... 22077434 - The 'overall yield' with the baseline series - a useful addition to the array of moahlf... 17167264 - Influence of fluoride dentifrice on brushing abrasion of eroded human enamel: an in sit... 15794454 - Use of a novel group of oral malodor measurements to evaluate an anti-oral malodor mout... 6195944 - Use of immunofluorescence, gram's staining, histologic examination, and seroagglutinati... 17619004 - Testing for hypothyroidism in dogs. |
Publication Detail:
|
Type: JOURNAL ARTICLE Date: 2011-9-20 |
Journal Detail:
|
Title: Molecular genetics and metabolism Volume: - ISSN: 1096-7206 ISO Abbreviation: - Publication Date: 2011 Sep |
Date Detail:
|
Created Date: 2011-10-21 Completed Date: - Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 9805456 Medline TA: Mol Genet Metab Country: - |
Other Details:
|
Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
|
Copyright © 2011 Elsevier Inc. All rights reserved. |
Affiliation:
|
Post-Graduation Program in Medicine: Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Perception of Mooney faces by young infants: The role of local feature visibility, contrast polarity...
Next Document: Time trends in testicular cancer in Croatia 1983-2007: Rapid increases in incidence, no declines in ...