The selective effect of Dscam overexpression on Drosophila neural circuits that control larval self-righting behaviour, without an effect on crawling speed, mirrors the more severe disruption of fine rather than gross motor skills of people with DS (Ferreira-Vasques and Lamônica, 2015, Marchal et al., 2016, Schott and Holfelder, 2015, Spanò et al., 1999). The gene discussed is DSCAM; the disease is Dravet syndrome.