April 10, 2013
Alzheimer Gene ABCA7 Significantly Increases Late-Onset Risk Among African Americans
Genetic study of late-onset Alzheimer disease in African Americans identifies unique risk levels
A variation in the gene ABCA7 causes a twofold increase in the risk of late onset Alzheimer disease among African Americans, according to a meta-analysis by a team of researchers including experts from the Perelman School of Medicine at the University of Pennsylvania. This is the largest analysis to date to determine genetic risk associated with late-onset Alzheimer disease (LOAD) specifically in African American individuals. The study appears in the April 10 issue of JAMA, a genomics theme issue.
"While the genotypes are similar between groups, the strength of risk is significantly different," said Schellenberg. "ABCA7 was previously identified to be weakly involved in the risk of Alzheimer disease among non-hispanics of European ancestry. Among African Americans, however, the gene is associated with a much stronger risk of late-onset Alzheimer disease."
African Americans have a higher incidence of late-onset AD, which affects 1 percent of people at age 65 years to more than 30 percent of people older than 80 years. As much as 20 percent of the disease-attributable risk is related to the APOe4 gene variation.
Researchers note that, if the study can be validated and replicated in additional studies, these findings may have "major implications for developing targets for genetic testing, prevention, and treatment."
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