Pyridoxine dependent epilepsy: Is late onset a predictor for favorable outcome?

Abstract

Objective: In pyridoxine dependent epilepsy (PDE), a neonatal epilepsy syndrome, a small subgroup is characterized by late-onset beyond 2 months of age. We aim to analyze the observation of relatively good cognitive outcome in this subgroup of late-onset PDE patients. Methods: We retrospectively analyzed data from four metabolically and genetically confirmed late-onset patients with PDE due to antiquitin (ALDH7A1) deficiency. Data were analyzed regarding ALDH7A1 mutations, alpha-Aminoadipic semialdehyde (α-AASA) and pipecolic acid (PA) levels, medication during pregnancy, delivery, treatment delay, amount of seizures, pyridoxine dose, adjuvant therapy and findings on brain MRI. Results: Results showed that three patients had relatively good outcome (IQ 80–97), while one patient was too young for formal testing and had mild developmental delay. We were unable to find a clear correlation between the above mentioned variables and cognitive outcome, although a less severe genotype was present in three patients, and maternal medication could be accountable for better outcome in two patients. Conclusion: We suggest that favorable outcome in late onset PDE could be explained by different genetic variations, functional variation and secondarily variation in treatment regimens and absence of neonatal seizure induced brain damage.