LAUSR

Pyridoxine-dependent epilepsy (PDE; MIM#266100), an early-onset epileptic encephalopathy, is an autosomal recessive inborn error of pyridoxine (vitamin B6) metabolism. PDE is due to mutations in the ALDH7A1 gene (MIM*107323) on chromo-some 5q31, fi rst described by A.D. Hunt Jr. in 1954. 1 The inci-dence of PDE is estimated from 1:20,000 to 1:800,000. 2 Antiquitin ( ALDH7A1 ) encodes α -amino adipic semialdehyde ( α -AASA) dehydrogenase involved in lysine metabolism. 2 Antiquitin de fi ciency, the most common form of PDE, leads to the accumulation of precursors, including α -AASA, pipecolic acid, and piperidine-6-carboxylate, thereby inactivating pyridoxal-5-phosphate and resulting in seizures. 3 Classically, PDE presents as persistent, recurrent neonatal seizures that can be partial or generalized, clonic, myoclonic, tonic, or infantile spasms refractory to antiseizure medications but respond clinically and electrographically to pyridoxine. 3 The wide phenotypic spectrum, apart from intractable epilepsy, includes perinatal complications with fetal distress, irritability, respiratory distress, and lactic acidosis. 4 Congenital cataracts are an unusual feature of the disorder. 2 Magnetic resonance imaging of the brain is normal in 50% of PDE cases, and common neuroimaging abnormalities include corpus callosum agenesis/hypoplasia (33%), nonspeci