A gene variant found almost exclusively among people of African descent appears to substantially raise the risk of Alzheimer’s disease, a new study finds.
The variant is in a gene called ApoE3, and it’s apparently only harmful when it exists in combination with the ApoE4 gene — a well-known risk factor for Alzheimer’s.
That gene duo was present in only 1% of the nearly 32,000 individuals in the study, all of African descent. But it was tied to a nearly threefold increase in the risk of developing Alzheimer’s, according to findings published Feb. 21 in the Journal of the American Medical Association.
Dr. Michael Greicius, the senior researcher on the study, pointed to one major reason the finding is important: Most of what’s known about the genetics of Alzheimer’s — and diseases in general — comes from studies of white people.
Meanwhile, some people do undergo genetic testing to see which ApoE forms they carry — often those with a strong family history of Alzheimer’s.
And it’s important, Greicius said, that doctors and genetic counselors understand that the influence of those genes can vary according to ancestry.
