A study of a sprawling family of 5,000 people in Colombia has led scientists to discover a network of nine key genes involved with the onset of Alzheimer's - a disease that's expected to affect one in 85 people globally by 2050.
Some of the genes delay the disease presenting itself, while others accelerate its onset, and if scientists can figure out how to manipulate these genes it’s possible we could hit pause on the condition for several years.
"If you can work out how to decelerate the disease, then you can have a profound impact," said Mauricio Arcos-Burgos, a medical geneticist at the Australian National University (ANU). "I think it will be more successful to delay the onset of the disease than to prevent it completely. Even if we delay the onset by on average one year, that will mean 9 million fewer people have the disease in 2050."
The Colombian family that participated in the study carry a type of hereditary Alzheimer’s disease and live in a specific region in the western mountains of the country. Genetically, they constitute a valuable resource for research in this area, given their size and how close-knit they are as a group.
"To the best of our knowledge, this is the largest analysed sample of patients with a unique mutation sharing uniform environment," the researchers write in Molecular Psychiatry.
Because of these factors, the US National Institute of Health is also interested in the family, and is looking into potential Alzheimer's disease treatments that the family has agreed to test.
The Australian scientists were interested in the variable age of onset that the Colombian family members experienced when it came to dementia. What they found, with the family’s cooperation, is that their genetic predisposition to Alzheimer's disease could be traced back to a founder mutation in one individual who came to their region approximately 500 years ago.
"This founder effect dates from the Spanish Conquistadors colonising Colombia during the early 16th century," the researchers write. "Of the more than 5,000 individuals descended from the original founder... 459 are mutation carriers and 722 are non-carriers of the mutation."
Having traced the mutation, the researchers were able to isolate nine genes involved in Alzheimer’s - some of which delay the onset of the disease by up to 17 years.
The researchers acknowledge that further studies will be needed to ensure that these gene variants affect the age of Alzheimer’s onset in broader populations outside this particular Colombian family, but if they do, it's hoped that therapeutic strategies will result.
"If we can modify lifestyle and age of onset using analogues of these molecules that we have been finding, I think that will be easier to change the heavy load that this condition is causing," Arcos-Burgos told Rachel Brown at the ABC.