ArticleJIMD reports2017
What Is the Best Blood Sampling Time for Metabolic Control of Phenylalanine and Tyrosine Concentrations in Tyrosinemia Type 1 Patients?
Article in JIMD reports, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers.
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Who cites it
9 citing papers in PubMed.
- Diagnosis, treatment, management and monitoring of patients with tyrosinaemia type 1: Consensus group recommendations from the German-speaking countries.Journal of inherited metabolic disease · 2025Review
- A 12-month, longitudinal, intervention study examining a tablet protein substitute preparation in the management of tyrosinemia.Molecular genetics and metabolism reports · 2024Article
- UK Dietary Practices for Tyrosinaemias: Time for Change.Nutrients · 2022Article
- Article
- Physical Growth of Patients with Hereditary Tyrosinaemia Type I: A Single-Centre Retrospective Study.Nutrients · 2021Article
- Natural Protein Tolerance and Metabolic Control in Patients with Hereditary Tyrosinaemia Type 1.Nutrients · 2020Article
- Dried blood spot versus venous blood sampling for phenylalanine and tyrosine.Orphanet journal of rare diseases · 2020Article
- Long-Term Outcomes and Practical Considerations in the Pharmacological Management of Tyrosinemia Type 1.Paediatric drugs · 2019Review
- The Effect of Various Doses of Phenylalanine Supplementation on Blood Phenylalanine and Tyrosine Concentrations in Tyrosinemia Type 1 Patients.Nutrients · 2019Article
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Authors and funding
9 authors.
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Abstract
backgroundTreatment of hereditary tyrosinemia type 1 with nitisinone and phenylalanine and tyrosine restricted diet has largely improved outcome, but the best blood sampling time for assessment of metabolic control is not known.
aimTo study diurnal and day-to-day variation of phenylalanine and tyrosine concentrations in tyrosinemia type 1 patients.
methodsEighteen tyrosinemia type 1 patients aged >1 year (median age 7.9 years; range 1.6-20.7) were studied. Capillary blood samples were collected 4 times a day (T1: pre-breakfast, T2: pre-midday meal, T3: before evening meal, and T4: bedtime) for 3 days. Linear mixed-effect models were used to investigate diurnal and day-to-day variation of both phenylalanine and tyrosine.
resultsThe coefficients of variation of phenylalanine and tyrosine concentrations were the lowest on T1 (13.8% and 14.1%, respectively). Tyrosine concentrations did not significantly differ between the different time points, but phenylalanine concentrations were significantly lower at T2 and T3 compared to T1 (50.1 μmol/L, 29.8 μmol/L, and 37.3 μmol/L, respectively).
conclusionOur results indicated that for prevention of too low phenylalanine and too high tyrosine concentrations, measurement of phenylalanine and tyrosine pre-midday meal would be best, since phenylalanine concentrations are the lowest on that time point. Our results also indicated that whilst blood tyrosine concentrations were stable over 24 h, phenylalanine fluctuated. Day-to-day variation was most stable after an overnight fast for both phenylalanine and tyrosine. Therefore, in tyrosinemia type 1 patients the most reliable time point for measuring phenylalanine and tyrosine concentrations to enable interpretation of metabolic control is pre-breakfast.
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