Scientists at Washington University School of Medicine in St. Louis have identified variations in a gene that double a person’s risk of developing Alzheimer’s disease later in life. Their research is published online in the journal Nature.
The newly identified variants were found in a gene—phospholipase-D 3 (PLD3)—never before linked to Alzheimer’s. Although the mutants are rare, they are important because individuals who carry them are at substantially increased risk for late-onset Alzheimer’s disease.
Lead author Carlos Cruchaga, Ph.D., is currently funded by BrightFocus for related genetics research. Co-investigator Alison Goate, DPhil., a past BrightFocus grantee, has served on the BrightFocus Scientific Review Committee for Alzheimer’s Disease.
Using a technique called whole exome sequencing, the scientists sequenced all the protein-coding genes from several individuals in 14 families. Some family members had the disease, others did not. From there, the scientists were able to go back and study another 11,000 people with and without the disease, and they were able to see that PLD3 gene variants “doubled the risk for the disease,” says Cruchaga, Assistant Professor in the Department of Psychiatry.
The approach used is just as important as the discovery, says Goate, the Samuel and Mae S. Ludwig Professor of Genetics in Psychiatry. By first studying gene variants within families they were able to narrow the number of variants that might cause disease. “If we had been using unrelated individuals, we would not have had the statistical power to find these rare variants,” she added