Mouse models of RCAN1 overexpression have shown a role of RCAN1 regulating exocytosis in chromaffin cells and in mutant huntingtin phosphorilation, suggesting a role of RCAN1 in the Alzheimer's disease neuropathology associated to DS and in Huntington's disease [8], [9], [10]. The gene discussed is RCAN1; the disease is Alzheimer disease.