Neurodegenerative disorders are common and devastating. Rationally, the most effective treatments will target pathogenetic mechanisms. While alternative - proaches, based on alleviating the symptoms of patients with Alzheimer disease, Parkinson disease, Huntington disease, prion disorders or amyotrophic lateral sc- rosis, can be expected to reduce suffering, studies of pathogenesis of these a- related disorders will be most important for enabling early diagnosis and the creation of preventative and curative treatments. It is in this context that a recent IPSEN rd meeting (The 23 Colloque...