PSEN1 and Alzheimer disease: Gatto and colleagues reported a novel PSEN1 mutation (p.Arg41Ser) in an Argentinian patient presenting with a motor phenotype characterized by good levodopa response, presence of levodopa induced dyskinesia, normal cognitive function in the absence of standard AD biomarkers (MRI moderate frontal cortical atrophy, negative research for cortical amyloid deposition and 18F-FDG-PET mild hypometabolism in left lateral temporal lobe) [13].