Lysine-restricted diet and mild cerebral serotonin deficiency in a patient with pyridoxine-dependent epilepsy caused by ALDH7A1 genetic defect

Pyridoxine dependent epilepsy (PDE) is caused by mutations in the ALDH7A1 gene (PDE-ALDH7A1) encoding alpha-aminoadipic-semialdehydedehydrogenase enzyme in the lysine catabolic pathway resulting in an accumulation of alpha-aminoadipic-acid-semialdehyde (alpha-AASA). We present the one-year treatment outcome of a patient on a lysinerestricted diet. Serial cerebral-spinal-fluid (CSF) alpha-AASA and CSF pipecolic-acid levels showed decreased levels but did not normalize. He had a normal neurodevelopmental outcome on a lysine-restricted diet. Despite normal CSF and plasma tryptophan levels and normal tryptophan intake, he developedmild CSF serotonin deficiency at one year of therapy. Stricter lysine restriction would be necessary to normalize CSF alpha-AASA levels, but might increase the risks associatedwith the diet. Patients are at risk of cerebral serotonin deficiency and should bemonitored by CSF neurotransmitter measurements. (C) 2014 The Authors. Published by Elsevier Inc.