The world's largest Alzheimer's study has made a gene discovery that could lead to treatments
Researchers have found two novel genes that increase an individual’s risk of developing Alzheimer’s disease (AD). This disorder is the leading cause of dementia and has an estimated heritability —genetic factor causing variation in the population, or an inherited trait— of 70%.
Details from the study
The research team worked with Cardiff University's Dementia Research Institute in the U.K. to reveal the new genes associated with the brain disorder that affects thinking and behavior, often starting with memory loss.
The study was published on Nov. 21 in the journal Nature Genetics.
Researchers from across the globe compared data that involved 32,558 genetic codes from both patients who had Alzheimer’s disease, and healthy participants. For the study, 16,036 individuals had Alzheimer’s disease and 16,522 individuals did not have AD.
New mutations found within genes that could cause Alzheimer's
The study found various new genes and certain mutations within those genes that can lead to the onset of developing Alzheimer’s disease. The new genes contain mutations that are rare, but also detrimental. These mutations were found in the genes called ATP8B4 and ABCA1, both of which could potentially lead to an increased risk of developing Alzheimer’s disease. They also discovered a genetic alternation — gene abnormality — in the gene known as ADAM10.
Researchers believe that the study allows them to assess variance in the immune system and brain processing. "These findings point us towards very specific processing in the brain, which includes differences in the brain's immune system and how the brain processes cholesterol. These differences impact brain functioning and leads to the development of Alzheimer's disease,” said Julie Williams, a professor, director of the Dementia Research Institute at Cardiff University, and a co-author on the study.
Exome sequencing data is used to identify variants of AD
In most assessments of AD, researchers used genome-wide association studies (GWAS), which are observational tests that look at all of the genetic information within DNA to find connections. However, GWAS does not catch the risk from rare variants of mutations. The researchers for this study used exome sequencing data to identify variants that cause Alzheimer’s disease. The statistics from exome sequencing is smaller than GWAS and allows for researchers to identify rare mutations.
Alzheimer’s disease currently has no cure. However, researchers believe that new discoveries of gene mutations can get them closer to discovering treatment options and preventative measures. Although older age is a risk factor for developing AD, younger people are starting to get early onset Alzheimer’s disease, which occurs in people between the ages of 30 to mid-60s. Genetic factors play a large role in developing AD early.
The future and knowing who is at risk for AD
The research allowed the team to understand who is most likely to develop AD by assessing the new gene mutations that can potentially increase the risk of developing this progressive disease. “This study helps expand our knowledge about who is at risk of developing this form of dementia. These genetic discoveries also allow us to understand the mechanisms underlying Alzheimer's, as well as create genetic models of the disease to develop targeted therapies in the future—through new drug-based treatments or even gene therapy,” Williams stated.