While neurons accounted for 39% of cells within the GCV-treated grafts, <25% of these NeuN+ neurons could be phenotyped as DAergic, GABAergic or Cholinergic (noting an absence of adrenergic/noradrenergic and, importantly, serotonergic neurons—a population previously linked to graft-induced dyskinesias in preclinical and clinical studies32,33). This evidence concerns the gene RBFOX3 and Dyskinesia.