Dietary amino acid intakes associated with a low-phenylalanine diet combined with amino acid medical foods and glycomacropeptide medical foods and neuropsychological outcomes in subjects with phenylketonuria

This article provides original data on median dietary intake of 18 amino acids from amino acid medical foods, glycomacropeptide medical foods, and natural foods based on 3-day food records obtained from subjects with phenylketonuria who consumed low-phenylalanine diets in combination with amino acid medical foods and glycomacropeptide medical foods for 3 weeks each in a crossover design. The sample size of 30 subjects included 20 subjects with classical phenylketonuria and 10 with a milder or variant form of phenylketonuria. Results are presented for the Delis-Kaplan Executive Function System and the Cambridge Neuropsychological Test Automated Battery; the tests were administered at the end of each 3-week dietary treatment with amino acid medical foods and glycomacropeptide medical foods. The data are supplemental to our clinical trial, entitled “Glycomacropetide for nutritional management of phenylketonuria: a randomized, controlled, crossover trial, 2016 (1) and “Metabolomic changes demonstrate reduced bioavailability of tyrosine and altered metabolism of tryptophan via the kynurenine pathway with ingestion of medical foods in phenylketonuria, 2017 (2). This data has been made public and has utility to clinicians and researchers due to the following: 1) This provides the first comprehensive report of typical intakes of 18 amino acids from natural foods, as well as amino acid and glycomacropeptide medical foods in adolescents and adults with phenylketonuria; and 2) This is the first evidence of similar standardized neuropsychological testing data in adolescents and adults with early-treated phenylketonuria who consumed amino acid and glycomacropeptide medical foods.

ingestion of medical foods in phenylketonuria, 2017 (2). This data has been made public and has utility to clinicians and researchers due to the following: 1) This provides the first comprehensive report of typical intakes of 18 amino acids from natural foods, as well as amino acid and glycomacropeptide medical foods in adolescents and adults with phenylketonuria; and 2) This is the first evidence of similar standardized neuropsychological testing data in adolescents and adults with early-treated phenylketonuria who consumed amino acid and glycomacropeptide medical foods.
& 2017 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Subject area
Biology, Medicine More specific subject area

Inherited Metabolic Disorders
Type of data Figure  The data presented are the first comparison of how ingestion of medical foods comprised primarily of single amino acids or intact protein from glycomacropeptide (a 64-amino acid glycophosphopeptide isolated from cheese whey) affect the dietary intake profile of amino acids.
The dietary intake of 18 amino acids provides useful information to clinicians and researchers related to typical amino acid intake of individuals with phenylketonuria.
The data from the standardized neuropsychological tests can be compared with pharmacological studies using these same tests to contrast the effectiveness of dietary management with pharmacological treatment in subjects with phenylketonuria [3,4].
These data are useful to clinicians and researchers evaluating the safety and efficacy of glycomacropeptide medical foods in the nutritional management of phenylketonuria.

Data
Summary data for dietary intake of amino acids and assessment of neuropsychological and executive function are presented for subjects with phenylketonuria enrolled in a randomized, controlled, crossover trial conducted from November 2010 to July 2015 [1,2]. These data are herein reported for the first time (Tables 1-3). The trial is registered at www.clinicaltrials.gov as NCT01428258 .

Experimental design
Thirty subjects with early-treated phenylketonuria, 20 with classical and 10 with a milder or variant form of phenylketonuria, completed the clinical trial [1]. The experimental design was a 2-stage, randomized, controlled, crossover trial where subjects followed their usual lowphenylalanine diet in combination with amino acid medical foods and glycomacropeptide medical foods for 3-weeks each at home (Fig. 1). The protocol included: a one-week baseline period for diet education and orientation to the protocol while consuming the usual amino acid medical foods, the  first 3-week dietary treatment with glycomacropeptide medical foods or amino acid medical foods, a 3-week washout period with return to the usual amino acid medical foods, a 1-week baseline period, and lastly the second 3-week dietary treatment with the glycomacropeptide medical foods or amino acid medical foods.

Materials and methods
Daily amino acid intake from the whole diet, medical foods, and natural food was calculated from consecutive 3-day food records at the end of the 3-week amino acid medical foods and glycomacropeptide medical foods treatments (Table 1). Amino acid calculations were performed by a Registered Dietitian skilled in standardized diet entry using Food Processor SQL (ESHA, version 10.12.0).
Neuropsychological testing to assess executive function, the Delis-Kaplan Executive Function System™ (Pearson Canada Assessment, Inc. Ontario, Canada), and the Cambridge Neuropsychological Test Automated Battery (Cambridge Cognition Ltd, Cambridge, UK) was conducted by research staff trained in the administration of standard psychological assessments under the supervision of a licensed psychologist after following the amino acid medical foods and glycomacropeptide medical foods treatments for 3 weeks (Tables 2-3).

Funding
This work was supported by Department of Health and Human Services Grants R01 FD003711 from the FDA Office of Orphan Products Development to Ney, P30-HD-03352, T32 DK007665 to Ney, and by the Clinical and Translational Science Award (CTSA) program, through the NIH National Center for Advancing Translational Sciences (NCATS), Grant UL1TR000427. Cambrooke Therapeutics, Inc. donated the glycomacropeptide medical foods used in this study.

Transparency document. Supplementary material
Transparency data associated with this article can be found in the online version at http://dx.doi. org/10.1016/j.dib.2017.06.004.