Creatine Levels in Patients with Phenylketonuria and Mild Hyperphenylalaninemia: A Pilot Study

Abstract

Background: Creatine (Cr) levels are strongly dependent on diets, including animal-derived proteins. Cr is an important metabolite as it represents a source of stored energy to support physical performance and potentially sustain positive effects such as improving memory or intelligence. This study was planned to assess Cr levels in PKU children adhering to a diet low in phenylalanine (Phe) content and compared with those of children with mild hyperphenylalaninemia (MHP) on a free diet. Methods: This retrospective pilot study analyzed Cr levels from Guthrie cards in 25 PKU and 35 MHP subjects. Anthropomorphic and nutritional data of the study populations were assessed, compared and correlated. Results: Cr levels of PKU subjects were significantly lower than those of MHP subjects and correlated to the low intake of animal proteins. Although no deficiencies in PKU subjects were identified, PKU subjects were found to have a 26-fold higher risk of displaying Cr levels <25° percentile than MHP counterparts. Conclusions: This pilot study suggests that Cr levels might be concerningly low in PKU children adhering to a low-Phe diet. Confirmatory studies are needed in PKU patients of different age groups to assess Cr levels and the potential benefits on physical and intellectual performance of Cr supplementation.

Phenylketonuria (PKU) Urinary Metabolomic Phenotype Is Defined by Genotype and Metabolite Imbalance: Results in 51 Early Treated Patients Using Ex Vivo 1H-NMR Analysis

“…The sources of creatine are mainly foods rich in meat, but creatine is also synthesized in the liver via glycine and arginine [35]. It is also decreased in the serum of PKU patients [36]. 3 show that tartaric and L-citramalic acid are both significantly elevated in PKU patients.…”

“…The sources of creatine are mainly foods rich in meat, but creatine is also synthesized in the liver via glycine and arginine [35]. It is also decreased in the serum of PKU patients [36]. Creatine plays an important role in energy metabolism.…”