New Finding Provides Additional Genetic Clues about Alzheimer's

Dorian Martin Health Guide
  • My friend, Kaye, emailed me this morning. She asked me whether I had heard the news story about a $99 genetic testing kit that would give you a full profile of your DNA. She’s considering doing this and wondered if I was thinking about it. I told her that my current thinking was “no,” since I’d become a huge hypochondriac and would worry about any memory slip if the news came back that I was genetically predisposed. Furthermore, there isn’t at this point a treatment for Alzheimer’s disease so that would even add to my worries.

    However, an international group of researchers are using the technology to identify new findings that, in turn, are identifying new genes related to Alzheimer’s and – hopefully – treatments that will stem the upcoming tsunami of dementia.

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    This group of researchers from around the globe has identified 11 new genes that are associated with late-onset Alzheimer’s disease. CBS News reported that prior to these findings, only 11 gene variants had been identified as being linked to late-onset Alzheimer’s disease; of those initial 11, Apolipoprotein E-e4 seemed to have the strongest link to increased risk.

    This finding, while scary in its implication that more people have a potential hereditary link to this disease, also means that researchers can now try to develop drugs based on this information. The study broadens the current view of the link between genetic factors and this type of dementia. In addition, the findings are expanding the link between Alzheimer’s and the immune system since they found a genetic overlap with several neurodegenerative diseases, such as multiple sclerosis and Parkinson’s disease.

    What also is interesting is that this team is comprised of members from the world’s largest research consortia on the genetics of Alzheimer’s disease. Formed in 2011, this group, called the International Genomics of Alzheimer’s Project (IGAP), collected genetic information from 25,500 people who have Alzheimer’s as well as 49,038 people without the disease; these participants were from 15 countries.

    In this study, the researchers scanned the brains of the study participants as part of the two-stage effort. This study not only identified 11 new genes linked to this type of dementia, but also found 13 other genes that need to be validated but that are believed to be linked to Alzheimer’s. One of the newly discovered gene variants is considered a landmark find because it has a large role in the area of the brain that controls how white blood cells that are involved in the immune system interact. This part of the brain also has been found to have ties with multiple sclerosis and Parkinson’s disease. The finding of this gene variant, known as HLA-DRB5/DRB1, suggests that the immune system and the development of Alzheimer’s may be linked.

    Pointing to the strong pattern emerging from the discovery of these gene variants, Dr. Julie Williams, a professor at the Neuroscience and Mental Health Research Institute at Cardiff University who lead part of the international study, said, "There is something in the immune response which is causing Alzheimer's disease and we need to look at that."

  • “This work demonstrates the enormous impact that global collaborations can have on genetic research. In less than three years since the International Genomics of Alzheimer’s Project formed, the IGAP team has identified more genes than had been identified in the previous 20 years,” said University of Miami Miller School Dean Pascal J. Goldschmidt in a press release. “This is a significant step forward in unlocking the genetic code of Alzheimer’s, which began in 1993 with Dr. Pericak-Vance’s discovery of apolipoprotein E as the major susceptibility gene of late-onset Alzheimer’s disease.”

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    These newly identified genes are believed to have a role in how the cells function, especially in their reaction to inflammation. Some gene variants also were found to affect brain cell function as well as function of the synapsis in the brain hippocampus, which deals with memory and learning.

    The good news in all of this is that researchers are getting a clearer understanding of the genetic background of Alzheimer’s. And the promising news is that researchers can use this information to begin to delve into treatments. So someday, I hope to tell Kaye that I will be glad to join her in taking a genetic test because there will be options available to stop this terrible disease.

    Primary Sources for This Sharepost:

    Castillo, M. (2013). 11 new gene variants linked to Alzheimer’s disease. CBS News.

    Lambert, J. C., et al. (2013). Meta-analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer’s disease. Nature Genetics.

    University of Miami Miller School of Medicine. (2013). International collaboration finds 11 new Alzheimer’s genes to target for drug discovery.

Published On: October 30, 2013