A team of researchers have uncovered the second gene for late-onset Alzheimer’s disease. Since the 1993 discovery of APOE, this latest gene, SORL1, was seen to be replicated in four distinct ethnic groups. The team believes that the reduction of SORL1 in the brain increases the likelihood of developing Alzheimer disease.
The team of scientists was led by Robert Friedland, M.D., professor in the department of neurology at Case School of Medicine in collaboration with an international effort led by Boston University School of Medicine (BUSM), the University of Toronto, and Columbia University Medical Center.
"Understanding how the forms of the SORL1 gene associated with increase risk alters protein handling will suggest novel pharmacological or lifestyle modifications to slow progression," predicts Dr. Friedland.
In a paper published in the February issue of Nature Genetics, researchers describe how variants in the SORL1 gene were found to be more common in people with late-onset Alzheimer's than in healthy people of the same age. The team suggests that these genetic variations alter the normal function of SORL1, resulting in Alzheimer’s disease. People with these genetic variants may not produce normal amounts of SORL1, implying that this gene has a protective function when working properly.
Another aspect of their findings was that the association between Alzheimer’s disease and SORL1 was replicated in four distinct ethnic groups: North American and European caucasians, African-Americans, Caribbean-Hispanics, and Arabs residing in Israel. Previous studies on the genetics of Alzheimer's used data from mostly Caucasian populations of American and European ancestry. This five-year study involved DNA samples from 6,000 volunteers.