To gain a greater understanding of the potential benefits of treatment with valproate, we have trialed its treatment on our transgenic zebrafish model of MJD that express enhanced green fluorescent protein (EGFP)-tagged human ataxin-3 protein containing either an expanded polyQ tract (84Q, representing disease causing) or a short, wild-type, polyQ tract (23Q), under a neuronal promoter (HuC/elavl3) [47]. The gene discussed is ATXN3; the disease is Machado-Joseph disease.