COLBOS (COLombia-BOSton) is a collaborative project between the Universidad de Antioquia, Medellin, Colombia and Massachusetts General Brigham, Boston. We work with an extraordinary kindred of approximately 6,000 individuals in Antioquia, Colombia, which contains roughly 1,500 carriers of an autosomal-dominant mutation (PSEN1 E280A).  These carriers are genetically determined to develop early onset Alzheimer’s disease, with almost 100% certainty, and have a well-characterized disease course, with mild cognitive impairment (MCI) occurring at a median age of 44, and dementia at 49. We collect neuropsychological, biomarker and neuroimaging data from our participants about every two years.