Mutations in Glutamic acid decarboxylase (GAD1), the human ortholog of elegans unc-25, are associated with autosomal recessive spastic cerebral palsy, a movement disorder caused by abnormalities in the brain; studies in elegans show that unc-25 is required for gamma-amino-butyric acid (GABA) synthesis and GABA-mediated behavioral functions; various GABA mutants in elegans, like unc-25, the GABA vesicular transporters (unc-46 and unc-47), and the GABA-A receptor, unc-49, all present head-bobbing convulsions.