Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Jun 22;28(13):4916.
doi: 10.3390/molecules28134916.

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

Claire Cannet  1 , Allan Bayat  2 , Georg Frauendienst-Egger  3 , Peter Freisinger  3 , Manfred Spraul  1 , Nastassja Himmelreich  4 , Musa Kockaya  5 , Kirsten Ahring  2 , Markus Godejohann  1 , Anita MacDonald  6 , Friedrich Trefz  7
Affiliations

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

Claire Cannet et al. Molecules. .

Abstract

Phenylketonuria (PKU) is a rare metabolic disorder caused by mutations in the phenylalanine hydroxylase gene. Depending on the severity of the genetic mutation, medical treatment, and patient dietary management, elevated phenylalanine (Phe) may occur in blood and brain tissues. Research has recently shown that high Phe not only impacts the central nervous system, but also other organ systems (e.g., heart and microbiome). This study used ex vivo proton nuclear magnetic resonance (1H-NMR) analysis of urine samples from PKU patients (mean 14.9 ± 9.2 years, n = 51) to identify the impact of elevated blood Phe and PKU treatment on metabolic profiles. Our results found that 24 out of 98 urinary metabolites showed a significant difference (p < 0.05) for PKU patients compared to age-matched healthy controls (n = 51) based on an analysis of urinary metabolome. These altered urinary metabolites were related to Phe metabolism, dysbiosis, creatine synthesis or intake, the tricarboxylic acid (TCA) cycle, end products of nicotinamide-adenine dinucleotide degradation, and metabolites associated with a low Phe diet. There was an excellent correlation between the metabolome and genotype of PKU patients and healthy controls of 96.7% in a confusion matrix model. Metabolomic investigations may contribute to a better understanding of PKU pathophysiology.

Keywords: Ex Vivo 1H-NMR analysis spectroscopy; genotype; metabolomics; pathogenesis; phenylketonuria.

PubMed Disclaimer

Conflict of interest statement

C.C., M.S. and M.G. are employees of Bruker Biospin, Ettlingen, Germany; otherwise, the authors declare no conflict of interest.

Figures

Figure 1
Figure 1
(A) Discrimination between classical PKU (cPKU) and healthy controls. PCA/CA/MCCV classification shows clear discrimination between cPKU (red ellipsoid) and an age-matched healthy control group (blue ellipsoid) with confusion of 96.7%. The space of discrimination is one representation of the modelling samples in two dimensions. The ellipsoids represent the 95% percentile of the model. (B) Prediction of mild PKU (mPKU) and non-determined genotype patients into the cPKU and healthy control model. Patients (except ID 137) with diamonds had a genotype phenotype value (GPV) of >2.7–6.9 and a phenotype of mPKU. Patients with green/black diamonds are not treated with sapropterin; green/yellow diamonds are treated. Patients with open diamonds have no classification because genotype was not available. Patient 385 has a phenotype between mPKU and hyperphenylalaninemia (HPA) according to [26].
Figure 2
Figure 2
Serum phenylalanine (Phe) level (µmol/L) by age for patients with PKU (n = 51).
Figure 3
Figure 3
Serum phenylalanine (Phe) level (µmol/L) by classical PKU (cPKU, n = 38) or mild PKU (mPKU, n = 13) phenotype. Patients indicated with open circles are treated with sapropterin dihydrochloride (tetrahydrobiopterin [BH4]).
Figure 4
Figure 4
Patients with mild PKU (mPKU) have a significantly higher natural protein intake per day than patients with classical PKU (cPKU). A few patients were on sapropterin treatment (mPKU, n = 7 and cPKU, n = 3, open circles).
Figure 5
Figure 5
NADH degradation products, N-methyl-2-pyridone-5-carboxamide (2PY) and N1-Methyl-4-pyridone-3-carboxamide (4PY) are elevated in PKU patients in comparison to healthy controls (HEA).
Figure 6
Figure 6
Oxaloacetic acid is significantly elevated in PKU patients in comparison to healthy controls (HEA).
Figure 7
Figure 7
Creatine (a) and guanidinoacetate (b) are slightly decreased in PKU patients in comparison to healthy controls (HEA).
Figure 8
Figure 8
Tartaric (a) and L-Citramalic (b) acid are significantly elevated in PKU patients in comparison to healthy controls (HEA).
Figure 9
Figure 9
(a) Allantoin is decreased in PKU patients, (b) Multifactorial analysis of allantoin using standard coefficient of variation: negative with age (p < 0.0001), and phenylalanine (Phe) level in plasma (not significant), and positive with natural protein intake (p < 0.0001).
Figure 10
Figure 10
Dimethylamine is decreased in PKU patients in comparison to healthy controls (HEA).
Figure 11
Figure 11
Possible influences on the human metabolome. In red are factors related to phenylketonuria and investigated in our study.
See this image and copyright information in PMC

References

    1. Van Wegberg A.M.J., MacDonald A., Ahring K., Bélanger-Quintana A., Blau N., Bosch A.M., Burlina A., Campistol J., Feillet F., Giżewska M., et al. The complete European guidelines on phenylketonuria: Diagnosis and treatment. Orphanet J. Rare Dis. 2017;12:162. doi: 10.1186/s13023-017-0685-2. - DOI - PMC - PubMed
    1. Vockley J., Andersson H.C., Antshel K.M., Braverman N.E., Burton B.K., Frazier D.M., Mitchell J., Smith W.E., Thompson B.H., Berry S.A. Phenylalanine hydroxylase deficiency: Diagnosis and management guideline. Genet. Med. 2014;16:188–200. doi: 10.1038/gim.2013.157. - DOI - PubMed
    1. Pilotto A., Blau N., Leks E., Schulte C., Deuschl C., Zipser C., Piel D., Freisinger P., Gramer G., Kölker S., et al. Cerebrospinal fluid biogenic amines depletion and brain atrophy in adult patients with phenylketonuria. J. Inherit. Metab. Dis. 2019;42:398–406. doi: 10.1002/jimd.12049. - DOI - PubMed
    1. Pilotto A., Zipser C.M., Leks E., Haas D., Gramer G., Freisinger P., Schaeffer E., Liepelt-Scarfone I., Brockmann K., Maetzler W., et al. Phenylalanine effects on brain function in adult phenylketonuria. Neurology. 2021;96:e399–e411. doi: 10.1212/WNL.0000000000011088. - DOI - PubMed
    1. Blau N., van Spronsen F.J., Levy H.L. Phenylketonuria. Lancet. 2010;376:1417–1427. doi: 10.1016/S0140-6736(10)60961-0. - DOI - PubMed