Metabolic Control in Patients With Phenylketonuria Pre- and Post-Sapropterin Loading Test

• Autor(a) principal: Barbosa,Catarina Sousa
• Data de Publicação: 2018
• Outros Autores: Almeida,Manuela F., Sousa,Cátia, Rocha,Sara, Guimas,Arlindo, Ribeiro,Rosa, Martins,Esmeralda, Bandeira,Anabela, Oliveira,Bruno M. P. M., Borges,Nuno, MacDonald,Anita, Rocha,Júlio C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of Inborn Errors of Metabolism and Screening
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2326-45942018000100307
• topic: phenylketonuria; BH4 loading test; metabolic control

Abstract In Portugal, tetrahydrobiopterin (BH4)-responsive patients with phenylketonuria (PKU) are identified using a loading test (LT). Phenylalanine/natural protein (Phe/NP) intake is increased to elevate blood Phe prior to the LT. In a longitudinal retrospective study, the impact of Phe/NP titration post-LT in 58 patients (19.6 + 8.2 years) with PKU during 4 study periods (SPs) was examined. In SP1 (2010-2013), patients were diet treated only; in SP2 (2014), the Phe/NP titration was followed by the LT in SP3 (2015). In SP4 (2016), patients received diet treatment only (n ¼ 49) or BH4 þdiet (n ¼ 9). The median percentage blood Phe within the target range was higher in SP1 versus SP4 (64 [28-85] vs 45 [0-66]; P < .001). Our results suggest that transient Phe/NP titration, associated with a deliberate increase in NP, may adversely affect metabolic control. Controlled studies are necessary to examine the longer term impact of temporary increased NP with BH4 LT in non-BH4-responsive patients.