The study, released Tuesday in the Journal of the American Medical Assn., was a genome-wide association study of 35,000 people. The researchers identified several genes linked to the disease but found that knowledge of these genes and their location on chromosomes did not improve their ability to predict who would develop Alzheimer's disease. The knowledge of genes related to the disease could, however, help with research into what causes it, the researchers concluded.
Identifying a number of genes involved in a disease that only have a small effect may not be very helpful, said Nancy L. Pedersen, of the Karolinska Institute in Sweden, in a commentary accompanying the study. She notes that Alzheimer's disease is highly hereditary but that only one known gene -- the APOE gene -- significantly increases the risk. The disease likely is the result of a number of genes, their combinations and, possibly, a combination of those genes and the environment.
The study, Pedersen writes, "is a fresh reminder that family history is very important, even for late-onset disease that was once thought to be sporadic." One's age, sex, family history and APOE status remain the most important factors for predicting risk of the disease.
-- Shari Roan
Photo: Steve Osman / Los Angeles Times