Similarly, for proteopathies such as Alzheimer's or Parkinson's disease, genetic duplications of APP or SNCA cause an earlier onset of what is recognizably the same disease, and triplications cause even more severe forms (Chartier‐Harlin et al, 2004; Rovelet‐Lecrux et al, 2006). The gene discussed is SNCA; the disease is Parkinson disease.