People with a common variation in a gene linked with coronary artery disease have nearly double the risk of developing Alzheimer's disease compared with others, U.S. researchers said on Wednesday.
The gene MTHFD1L helps control production of the amino acid homocysteine in the blood. Different variations of the gene have been linked with a higher risk of coronary artery disease.
Because blood vessel function may also play a role in Alzheimer's, the finding may help explain the role of homocysteine in both conditions.
"Identifying this gene is important because the gene is known to be involved in influencing the body's levels of homocysteine," Margaret Pericak-Vance of the University of Miami, who led the research presented on Wednesday at the American Academy of Neurology meeting in Toronto.
The finding adds to a growing understanding of the genetic basis for Alzheimer's disease, a mind-wasting condition for which there are few treatments and no cure and which affects 26 million people globally.
"We are hopeful our identification of MTHFD1L as a risk gene for Alzheimer's disease will help us to better understand how this disease develops and potentially serve as a marker for people who may be at increased risk," Adam Naj of the University of Miami, who worked on the study, said in a statement.
Pericak-Vance and colleagues looked at slight differences in the genetic code of 2,269 people with late-onset Alzheimer's disease and 3,107 people without the disease.
Despite decades of research, doctors still have few treatments for Alzheimer's disease, which is expected to affect 100 million people by 2050.
Identifying people who are at risk may help them take steps to prevent or delay the disease, such as exercising and eating a diet low in saturated fat.