We have located links that may give you full text access.
Case Reports
Journal Article
Research Support, Non-U.S. Gov't
Pyridoxine-5'-phosphate oxidase (Pnpo) deficiency: Clinical and biochemical alterations associated with the C.347g>A (P.·Arg116gln) mutation.
Molecular Genetics and Metabolism 2017 September
BACKGROUND: Pyridoxal-5' -phosphate oxidase (PNPO) deficiency presents as a severe neonatal encephalopathy responsive to pyridoxal-5' -phosphate (PLP) or pyridoxine. Recent studies widened the phenotype of this condition and detected genetic variants on PNPO gene whose pathogenic role and clinical expression remain to be established.
OBJECTIVE: This paper aims to characterize the functional effects of the c.347G>A (p.Arg116Gln) mutation in the PNPO gene in order to define its pathogenicity and describe the clinical features of new patients with epilepsy carrying this mutation.
METHODS: Arg116Gln protein variant was expressed as recombinant protein. The mutant protein was characterized with respect to structural and kinetic properties, thermal stability, binding constants of cofactor (FMN) and product (PLP). We also reviewed clinical data of 3 new patients carrying the mutation.
RESULTS: The Arg116Gln mutation does not alter the overall enzyme structure and only slightly affects its catalytic efficiency; nevertheless, this mutation affects thermal stability of PNPO, reduces its affinity for FMN and impairs transfer of PLP to PLP-dependent enzymes. Three boys with seizure onset between 8months and 3years of age, carrying the Arg116Gln mutation, are described. These three patients exhibited different seizure types associated with interictal EEG abnormalities and slow background activity. Mild/moderate intellectual disability was observed in 2/3 patients. A dramatic therapeutic response to pyridoxine was observed in the only patient who still had active seizures when starting treatment, while in all three patients interictal EEG discharges and background activity improved after pyridoxine treatment was initiated.
CONCLUSIONS: The reported data support a pathogenic role of the c.347G>A (p.Arg116Gln) mutation in PNPO deficiency. The later onset of symptoms and the milder epilepsy phenotype of these expand the disease phenotype.
OBJECTIVE: This paper aims to characterize the functional effects of the c.347G>A (p.Arg116Gln) mutation in the PNPO gene in order to define its pathogenicity and describe the clinical features of new patients with epilepsy carrying this mutation.
METHODS: Arg116Gln protein variant was expressed as recombinant protein. The mutant protein was characterized with respect to structural and kinetic properties, thermal stability, binding constants of cofactor (FMN) and product (PLP). We also reviewed clinical data of 3 new patients carrying the mutation.
RESULTS: The Arg116Gln mutation does not alter the overall enzyme structure and only slightly affects its catalytic efficiency; nevertheless, this mutation affects thermal stability of PNPO, reduces its affinity for FMN and impairs transfer of PLP to PLP-dependent enzymes. Three boys with seizure onset between 8months and 3years of age, carrying the Arg116Gln mutation, are described. These three patients exhibited different seizure types associated with interictal EEG abnormalities and slow background activity. Mild/moderate intellectual disability was observed in 2/3 patients. A dramatic therapeutic response to pyridoxine was observed in the only patient who still had active seizures when starting treatment, while in all three patients interictal EEG discharges and background activity improved after pyridoxine treatment was initiated.
CONCLUSIONS: The reported data support a pathogenic role of the c.347G>A (p.Arg116Gln) mutation in PNPO deficiency. The later onset of symptoms and the milder epilepsy phenotype of these expand the disease phenotype.
Full text links
Related Resources
Trending Papers
Consensus Statement on Vitamin D Status Assessment and Supplementation: Whys, Whens, and Hows.Endocrine Reviews 2024 April 28
The Tricuspid Valve: A Review of Pathology, Imaging, and Current Treatment Options: A Scientific Statement From the American Heart Association.Circulation 2024 April 26
British Society of Gastroenterology guidelines for the management of hepatocellular carcinoma in adults.Gut 2024 April 17
Interstitial Lung Disease: A Review.JAMA 2024 April 23
Ventilator Waveforms May Give Clues to Expiratory Muscle Activity.American Journal of Respiratory and Critical Care Medicine 2024 April 25
Systemic lupus erythematosus.Lancet 2024 April 18
Acute Kidney Injury and Electrolyte Imbalances Caused by Dapagliflozin Short-Term Use.Pharmaceuticals 2024 March 27
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app