Three decades ago, UC Santa Barbara neuroscientist Kenneth S. Kosik(link is external) first started studying a Colombian family afflicted with a genetic form of early-onset Alzheimer’s disease. He and fellow researchers realized that they were only scratching the surface of largely invisible, yet profound, consequences of the colonization carried out by the Spanish almost five centuries in the past.

“When my colleagues were conducting this clinical trial on the individuals in this very large rural family that carried this mutation, they needed as many participants as possible,” Kosik said, recalling efforts to recruit people for the study. The family in question, which comprises several thousand people, was unique. Members that carried the so-called Paisa mutation would, like clockwork, begin to develop the hallmark forgetfulness of Alzheimer’s — what they called la bobera — in their 40s. Working with Colombian neuroscientist Francisco Lopera, the researchers tried to cast as wide a net as they could to find even those in remote parts of the country with early-onset dementia that caused so much undue suffering in Colombia.