If additional studies confirm the findings, the SORL1 gene would be the second genetic risk factor for this disease, usually diagnosed after age 65, researchers said in the February issue of Nature Genetics.
The key event in Alzheimer's disease is the generation of A-beta peptide from a protein called amyloid precursor protein (APP), researchers said. The A-beta peptide is thought to trigger the neuro-degeneration that characterizes the disease.
University of Toronto scientist Peter St. George-Hyslop and colleagues from U.S. universities and medical institutions looked for variants in genes encoding several APP-processing proteins for the potential link. The team identified two clusters of variants in SORL1 that were significantly higher in patients with the disease.
The team said it showed that reducing the level of SORL1 in cultured cells promoted production of A-beta peptide, suggesting a potential link of SORL1 variants increasing neuro-degeneration risk.
The team said it also found preliminary evidence that Alzheimer's patients tend to have lower levels of SORL1 in their blood cells.
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