Usage Information
Citation Information: J Clin Invest. 2021;131(15):e148272. https://doi.org/10.1172/JCI148272.
Abstract
Background Pyridoxine-dependent epilepsy (PDE-ALDH7A1) is an inborn error of lysine catabolism that presents with refractory epilepsy in newborns. Biallelic ALDH7A1 variants lead to deficiency of α-aminoadipic semialdehyde dehydrogenase/antiquitin, resulting in accumulation of piperideine-6-carboxylate (P6C), and secondary deficiency of the important cofactor pyridoxal-5′-phosphate (PLP, active vitamin B6) through its complexation with P6C. Vitamin B6 supplementation resolves epilepsy in patients, but intellectual disability may still develop. Early diagnosis and treatment, preferably based on newborn screening, could optimize long-term clinical outcome. However, no suitable PDE-ALDH7A1 newborn screening biomarkers are currently available.Methods We combined the innovative analytical methods untargeted metabolomics and infrared ion spectroscopy to discover and identify biomarkers in plasma that would allow for PDE-ALDH7A1 diagnosis in newborn screening.Results We identified 2S,6S-/2S,6R-oxopropylpiperidine-2-carboxylic acid (2-OPP) as a PDE-ALDH7A1 biomarker, and confirmed 6-oxopiperidine-2-carboxylic acid (6-oxoPIP) as a biomarker. The suitability of 2-OPP as a potential PDE-ALDH7A1 newborn screening biomarker in dried bloodspots was shown. Additionally, we found that 2-OPP accumulates in brain tissue of patients and Aldh7a1-knockout mice, and induced epilepsy-like behavior in a zebrafish model system.Conclusion This study has opened the way to newborn screening for PDE-ALDH7A1. We speculate that 2-OPP may contribute to ongoing neurotoxicity, also in treated PDE-ALDH7A1 patients. As 2-OPP formation appears to increase upon ketosis, we emphasize the importance of avoiding catabolism in PDE-ALDH7A1 patients.Funding Society for Inborn Errors of Metabolism for Netherlands and Belgium (ESN), United for Metabolic Diseases (UMD), Stofwisselkracht, Radboud University, Canadian Institutes of Health Research, Dutch Research Council (NWO), and the European Research Council (ERC).
Authors
Udo F.H. Engelke, Rianne E. van Outersterp, Jona Merx, Fred A.M.G. van Geenen, Arno van Rooij, Giel Berden, Marleen C.D.G. Huigen, Leo A.J. Kluijtmans, Tessa M.A. Peters, Hilal H. Al-Shekaili, Blair R. Leavitt, Erik de Vrieze, Sanne Broekman, Erwin van Wijk, Laura A. Tseng, Purva Kulkarni, Floris P.J.T. Rutjes, Jasmin Mecinović, Eduard A. Struys, Laura A. Jansen, Sidney M. Gospe Jr., Saadet Mercimek-Andrews, Keith Hyland, Michèl A.A.P. Willemsen, Levinus A. Bok, Clara D.M. van Karnebeek, Ron A. Wevers, Thomas J. Boltje, Jos Oomens, Jonathan Martens, Karlien L.M. Coene
Usage data is cumulative from May 2024 through May 2025.
| Usage | JCI | PMC |
|---|---|---|
| Text version | 1,244 | 294 |
| 187 | 104 | |
| Figure | 505 | 2 |
| Table | 91 | 0 |
| Supplemental data | 150 | 9 |
| Citation downloads | 88 | 0 |
| Totals | 2,265 | 409 |
| Total Views | 2,674 | |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)