Pyridoxine-dependent and other pyridoxine-responsive epilepsies-insights into phenotype overlapping and the long-term outcome in a cohort of 21 children.

Aim: Evaluation of etiology, phenotype, and long-term outcome, and defining the predictors of outcome in children with pyridoxine-responsive seizures. Methods: The study included all children with pyridoxine-responsive seizures treated in our hospital from 2006 to 2025. Serial video electroencephalography, brain MRI, metabolic, genetic analyses, and psychological assessment were done in all cases. All patients were divided into two groups: patients with pyridoxine-dependent epilepsy (PDE) associated with pathogenic variants in Results: Twenty-one patients were included: 10 in group I and 11 in group II with various etiologies. Median age at seizure onset in both cohorts was 2 (range 1-11) days. Mann-Whitney U test demonstrated no significant difference between the two groups ( Discussion: Etiologic heterogeneity and phenotype overlapping between PDE and PRE, atypical presentations, and good initial response to pyridoxine regardless of genetic and neuroimaging findings suggest the introduction of pyridoxine in all infants when two ASMs have failed. Despite appropriate pyridoxine treatment, more than half of patients with PDE had developmental delay and resistant seizures, suggesting the complexity of the underlying mechanisms.