A single gene mutation, presenilin 1 (PSEN1), could significantly alter the trajectory of Alzheimer's disease, according to new research from the University of Texas Southwestern Medical Center. The mutation affects a protein called reelin, which directs brain cells to destroy toxic amyloid plaques and tau tangles. The finding could lead to transformative therapies for the condition. Neuroscientist Lopera, who led the research, identified thousands of people affected by a rare genetic form of Alzheimer’s disease in Colombia who lived well into his 60s before developing Alzheimer's. The COLBOS mutation, named after the research centers in Colombia and Boston that characterized it, altered how reelin binds to another signaling molecule, heparan sulfate. The change explains why the mutation was able to ward off Alzheimer's, and could potentially cause reelin to accumulate at the surface of neurons.