Study Looks at Family History for Late-Onset Alzheimer's

Dorian Martin Health Guide
  • My mother was diagnosed with Alzheimer’s disease when she was in her 80s. Her brother (my uncle) had Alzheimer’s disease in later life. Their mother (my grandmother) had some sort of dementia in her 80s. So does that mean I will get this terrible condition?


    I know I’m not alone in worrying about it. Many people – especially those in a caregiving situation for a loved one with Alzheimer’s who get a first-hand view of what it’s like – share my concern. And the research about the strongest possibility of a genetic link involves early-onset Alzheimer’s, which none of my relatives had.

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    Study Identifies Silent Brain Changes


    Well, a new study suggests that while my risk of experiencing changes in my brain is increased, it’s not a done deal that I will develop Alzheimer’s disease.  This study, which is out of Duke University, focused on brain scans of 257 people between the ages of 55 and 89. These individuals were divided into three groups based on whether they were cognitively normal, had mild cognitive impairment or had Alzheimer’s disease.


    The researchers also looked at cerebrospinal fluid as well as different measures in the brain, such as the levels of tau and hippocampal volumes. They also analyzed the participants’ genes.


    Their analysis concluded that having a parent, brother or sister who has been diagnosed with Alzheimer’s disease increases the possibility that an individual will have silent brain changes. Furthermore, approximately 50 percent of health participants who had a family history of Alzheimer’s would have met the criteria for early Alzheimer’s disease based on the results of the analysis of the cerebrospinal fluid. In comparison, approximately 20 percent of participants who did not have a family history of Alzheimer disease have met these criteria.


    Whereas researchers have found a compelling link between family genetics and early-onset Alzheimer’s and have developed a test related to this, the data from late-onset Alzheimer’s isn’t so clear cut. "The genetics are much more complex, and although we know these individuals are at a slightly greater risk, we don't know when they start developing silent brain changes," said Dr. P. Murali Doraiswamy, a professor of psychiatry and medicine at Duke University and the study’s senior author. "[The new study is] documenting very clearly that asymptomatic family members have twice the rate of silent brain changes and that these changes happen in certain pathways known to be related to Alzheimer's disease."


    Taking a Proactive Approach


    So if you’re like me and have a family member who had Alzheimer’s disease, what should you do? First of all, don’t go off the deep end and worry. While you do have a higher risk for developing this condition, having a parent or sibling with this disease doesn’t mean that you will. I point you to the Nun’s Study, in which one nun’s brain showed all the hallmarks of Alzheimer’s disease upon autopsy. However, the researchers who interacted with this nun while she was still alive did not see any signs of the memory loss and behaviors that are common with Alzheimer’s disease and, thus, were totally surprised when they found out the results of the autopsy.


  • Although the researchers who led the Nun Study didn’t pinpoint why this nun didn’t experience any cognitive changes even though her brain showed the plaques and tangles that are consistent with Alzheimer’s, it does provide hope that we don’t have go down a preordained path.

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    So what can we do? Experts encourage people who are worried about Alzheimer’s and other dementia to adopt healthy behaviors as early as possible. These behaviors include exercise, eating a healthy diet, easing stress, staying mentally active, and maintaining social relationships. And those steps are worth it if it will help us delay or prevent this terrible condition.


    Primary Sources for This Sharepost:


    Lambert, E. J., et al. (2013).  Prevalence of Alzheimer’s pathologic endophenotypes in asymptomatic and mildly impaired first-degree relatives. PLOS One.


    Medline Plus. (2013). Brain changes seen in relatives of people with Alzheimer’s.

Published On: April 23, 2013