GAD2 and epilepsy: Altered γ-aminobutyric acid (GABA) status has been found in the brain tissues of rodents fed with a VD deficient diet [34] and we recently found that chronic administration of 1,25-dihydroxyvitamin D [1,25(OH)2D], the active form of VD, can elevate GABA concentrations and promote glutamate decarboxylase (GAD) 67 and GAD65 mRNA expression in rat brain [6], whereas attenuated GABAergic neurotransmission is highly relevant to the progression of epilepsy [35].