GLUL and epilepsy: Among its functions in the CNS, pyridoxal acts as a co‐factor for glutamate decarboxylase, which synthesizes γ‐aminobutyric acid (GABA), one of the main inhibitory neurotransmitters in the CNS, from glutamate; decreased GPI‐anchored TNAP, therefore, has been suggested to lead to GABA deficiency, contributing to the pathogenesis of epilepsy in patients with GPI‐anchor deficiencies.12, 23