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Pyridoxal phosphate-responsive seizures

Synonyms
EPILEPTIC ENCEPHALOPATHY, NEONATAL, PNPO-RELATED; Pyridoxal 5'-phosphate-dependent epilepsy; Pyridoxamine 5-Prime-Phosphate Oxidase Deficiency; Pyridoxine-5'-phosphate oxidase deficiency; SEIZURES, PYRIDOXINE-RESISTANT, PLP-SENSITIVE
Modes of inheritance
Autosomal recessive inheritance (Orphanet)

Summary

Excerpted from the GeneReview: PNPO Deficiency
Untreated pyridox(am)ine 5'-phosphate oxidase (PNPO) deficiency, characterized by a range of seizure types, is "classic" (i.e., seizure onset in the neonatal period) in about 90% of affected individuals and "late onset" (seizure onset after the neonatal period) in about 10%. In classic PNPO deficiency, seizures (including status epilepticus) often begin on the first day of life and typically before age two weeks. In both classic and late-onset untreated PNPO deficiency, seizure semiology varies from myoclonic to clonic or tonic seizures, and seizures are typically resistant to common anti-seizure medications. Independent of age of onset, seizures respond to life-long treatment with a B6 vitamer: pyridoxal 5'-phosphate (PLP) in about 60% of affected individuals and pyridoxine (PN) in about 40%. About 60% of individuals with PNPO deficiency have developmental impairment, affecting speech, cognition, and behavior; some individuals have neurologic impairment such as muscular hypotonia or dystonia. Severe neurodevelopmental impairment is more likely to occur in individuals with PNPO deficiency who experienced diagnostic delay and prolonged periods of uncontrolled seizures.
Full text of GeneReview (by section):
Summary
GeneReview Scope
Diagnosis
Clinical Characteristics
Genetically Related (Allelic) Disorders
Differential Diagnosis
Management
Genetic Counseling
Resources
Molecular Genetics
Chapter Notes
References
Authors:
Barbara Plecko
Philippa Mills
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Available tests

60 tests are in the database for this condition.

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Clinical tests (60 available)

Biochemical Genetics Tests

Molecular Genetics Tests

Genes See tests for all associated and related genes

  • Also known as: HEL-S-302, PDXPO, PNPO
    Summary: pyridoxamine 5'-phosphate oxidase

Clinical features

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Imported from Human Phenotype Ontology (HPO)

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