A slight difference in DNA could shape some peoples’ susceptibility to developing Alzheimer’s disease, researchers have found.

Experts based at various institutions in Hong Kong found that Chinese participants with longer repeats of a specific gene sequence in their DNA were more likely to have the disease. The association was also noted among European participants, although it was much weaker.

The study was published in the journal Nature Neuroscience on October 12.

Researchers have previously identified several genetic variants that are believed to be associated with Alzheimer’s risk, and it is understood that those who have a parent or sibling diagnosed with the disease are more likely to develop it than people without those links—although this doesn’t mean that person will develop Alzheimer’s, it only increases the odds.

That said, Alzheimer’s does not have a single genetic cause, and is believed instead to be influenced by a combination of genetic, lifestyle and environmental factors.

What the experts set out to understand in this study was whether repeats of certain genetic sequences—rather than specific genetic variants—could influence risk.

Rudolph Tanzi, a professor of neurology at Harvard University, told Newsweek that the “potentially important” study “goes beyond the normal single-base genome variants that are tested in the many genome-wide association studies of Alzheimer’s disease.”

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