The Tc1 mouse model of DS, used in this study, contains a freely-segregating copy of Hsa21 in addition to a full complement of mouse chromosomes (O'Doherty et al., 2005) and is trisomic for more than 75% of Hsa21 protein encoding genes, including DYRK1A (S. Gribble, Wellcome Trust, Sanger Institute, personal communication). The gene discussed is DYRK1A; the disease is Dravet syndrome.