Normal Growth in PKU Patients Under Low-Protein Diet in a Single-Center Cross-Sectional Study
Dietary phenylalanine restriction in phenylketonuria (PKU) patients is usually mandatory in order to prevent cognitive impairment. The influence of a low-protein diet on growth has raised concerns in families and caregivers. This paper aims to investigate the growth in PKU patients treated with a low-protein diet including supplementation of amino acids and other nutrients according to standard protocols.
We performed a single-center, cross-sectional study on growth in pediatric PKU patients (n = 51) treated with low-protein diet over a 20-month period. Height of healthy siblings (n = 44) and target height, calculated based on parents’ height, served as controls.
No statistically significant differences were found comparing mean height z-scores between patients and siblings (p = 0.261). Patients <12 years showed a reduction in mean height z-scores compared to the target height (p = 0.020), whereas postpubertal patients ≥12 years did not differ significantly in height z-scores compared to the target height (p = 0.071). Healthy siblings’ height did not differ from target height in neither age group (p = 0.100/p = 0.301).
Our results suggest that PKU patients treated with low-protein diet can achieve normal growth with patients making up the leeway after puberty. While prepubertal patients were shorter than expected based on their target height, older patients were within their expected target height. This study indicates that current practice of low-protein diet in PKU patients allows normal growth.
KeywordsGrowth Low-protein diet Phenylketonuria PKU Target height
We are obliged to all patients and their families who took part in this study. We would also like to thank Nathalie Wunderli and Priska Wuhrbach for their help in measuring the patients’ height. We also gratefully acknowledge the access to height percentiles elaborated by the Department of Developmental Paediatrics of the University Children’s Hospital Zurich under the direction of Prof. Dr. O. Jenni.
- Braegger C, Jenni O, Konrad D, Molinari L (2011) Neue Wachstumskurven für die Schweiz. Paediatrica 22:9–11Google Scholar
- Burgard P, Ullrich K, Ballhausen D, Hennermann JB, Hollak CEM, Langeveld M, Karall D, Konstantopoulou V, Maier EM, Lang F, Lachmann R, Murphy E, Garbade S, Hoffmann GF, Kolker S, Lindner M, Zschocke J (2017) Issues with European guidelines for phenylketonuria. Lancet Diabetes Endocrinol 5:681–683CrossRefGoogle Scholar
- Diamond A, Prevor MB, Callender G, Druin DP (1997) Prefrontal cortex cognitive deficits in children treated early and continuously for PKU. In: Monographs of the Society for Research in Child Development. University of Chicago Press, Chicago, pp i–206Google Scholar
- Hoeksma M, Van Rijn M, Verkerk PH, Bosch AM, Mulder MF, de Klerk JB, De Koning TJ, Rubio-Gozalbo E, De Vries M, Sauer PJ (2005) The intake of total protein, natural protein and protein substitute and growth of height and head circumference in Dutch infants with phenylketonuria. J Inherit Metab Dis 28:845–854CrossRefGoogle Scholar
- Shapiro HL, Hulse FS (1939) Migration and environment: a study of the physical characteristics of the Japanese immigrants to Hawaii and the effects of environment on their descendants. Oxford University Press, OxfordGoogle Scholar
- van Spronsen FJ, van Wegberg AM, Ahring K, Belanger-Quintana A, Blau N, Bosch AM, Burlina A, Campistol J, Feillet F, Gizewska M, Huijbregts SC, Kearney S, Leuzzi V, Maillot F, Muntau AC, Trefz FK, van Rijn M, Walter JH, MacDonald A (2017) Key European guidelines for the diagnosis and management of patients with phenylketonuria. Lancet Diabetes Endocrinol 5:743–756CrossRefGoogle Scholar