AbstractRecently, α‐aminoadipic semialdehyde (α‐AASA) dehydrogenase deficiency was shown to cause pyridoxine‐dependent epilepsy in a considerable number of patients. α‐AASA dehydrogenase deficiency is an autosomal recessive disorder characterized by a neonatal‐onset epileptic encephalopathy in which seizures are resistant to antiepileptic drugs but respond immediately to the administration of pyridoxine (OMIM 266100). Increased plasma and urinary levels of α‐AASA are associated with pathogenic mutations in the α‐AASA dehydrogenase (ALDH7A1/antiquitin) gene. Here, we report an intriguing “silent” mutation in ALDH7A1, a novel missense mutation and a founder mutation in a Dutch cohort (10 patients) with α‐AASA dehydrogenase deficiency. Ann Neurol 2007