TY - JOUR
T1 - Administration of protein substitute and quality of control in phenylketonuria: a randomised study
AU - MacDonald, Anita
AU - Rylance, George
AU - Davies, P
AU - Asplin, D
AU - Hall, Susan
AU - Booth, Ian
PY - 2003/1/1
Y1 - 2003/1/1
N2 - Uneven administration of an L-amino acid protein substitute is an important contributing factor in variability in plasma phenylalanine concentrations over the 24-hour period in patients with phenylketonuria under treatment. The aim of this study was to determine whether manipulating the timing of protein substitution would reduce variability in plasma phenylalanine over 24 h. Sixteen children (aged 1-11 years) with well-controlled phenylketonuria were entered into a randomized crossover study in which four protocols of the same daily dose of protein substitute administration were compared. In protocol A, three equal, divided doses were given with meals over 10 h; in protocol B, three equal doses over 14 h; in protocol C, four equal doses over 14 h; and in protocol D, six equal doses over 24 h (3 subjects only). Four-hourly skin puncture blood specimens were collected for 48 h in each study protocol. In protocols A, B and C, but not in protocol D, there was wide variability in 24 h plasma phenylalanine. The median daily differences (mumol/L) between highest and lowest phenylalanine concentrations were: for protocol A, 140; for protocol B, 100; for protocol C, 120; and for protocol D, 40. In protocol D, 97% of all phenylalanine concentrations were below 120 mumol/L and no concentration fell below 40 mumol/L. Administration of protein substitute overnight as well as during daytime produces stable and lower plasma phenylalanine concentrations and may lead to improved dietary phenylalanine tolerance.
AB - Uneven administration of an L-amino acid protein substitute is an important contributing factor in variability in plasma phenylalanine concentrations over the 24-hour period in patients with phenylketonuria under treatment. The aim of this study was to determine whether manipulating the timing of protein substitution would reduce variability in plasma phenylalanine over 24 h. Sixteen children (aged 1-11 years) with well-controlled phenylketonuria were entered into a randomized crossover study in which four protocols of the same daily dose of protein substitute administration were compared. In protocol A, three equal, divided doses were given with meals over 10 h; in protocol B, three equal doses over 14 h; in protocol C, four equal doses over 14 h; and in protocol D, six equal doses over 24 h (3 subjects only). Four-hourly skin puncture blood specimens were collected for 48 h in each study protocol. In protocols A, B and C, but not in protocol D, there was wide variability in 24 h plasma phenylalanine. The median daily differences (mumol/L) between highest and lowest phenylalanine concentrations were: for protocol A, 140; for protocol B, 100; for protocol C, 120; and for protocol D, 40. In protocol D, 97% of all phenylalanine concentrations were below 120 mumol/L and no concentration fell below 40 mumol/L. Administration of protein substitute overnight as well as during daytime produces stable and lower plasma phenylalanine concentrations and may lead to improved dietary phenylalanine tolerance.
UR - http://www.scopus.com/inward/record.url?scp=0042420698&partnerID=8YFLogxK
U2 - 10.1023/A:1025186217369
DO - 10.1023/A:1025186217369
M3 - Article
C2 - 12971419
VL - 26
SP - 319
EP - 326
JO - Journal of Inherited Metabolic Disease
JF - Journal of Inherited Metabolic Disease
ER -