The Value of Genetic Testing in Alzheimer’s

ABC News’ Terry Moran wrote a poignant piece on why he decided to get tested for the gene that carries markers that are linked to Alzheimer’s disease. He states that he has a strong family history of Alzheimer’s and wanted to take the test not only to know more about his future health, but also to take responsibility for his own health. He does state that this test does not definitively predict whether or not he will get Alzheimer’s. It only gives statistical information based on his innate genetic risks. It ends up that he has a 19% chance of getting Alzheimer’s. It’s about 10% greater than the average population.  

Alzheimer’s is a devastating disease, not only for the patient, but also for the immediate family members. Research so far has focused on the molecular and genetic mechanisms, with progress being made day by day. However, I can’t help but to wonder if we’re going about this the wrong way. 

 

Let me explain: We know that Alzheimer’s is linked with cardiovascular conditions such as heart disease, heart attack and stroke. Untreated obstructive sleep apnea is a major risk factor for developing heart disease and significantly increasing your risk for sudden cardiac death and stroke. Sleep apnea is something that you don’t just develop when you’re older—you’ve had some degree of it all your life. 

 

Recent sophisticated imaging studies have revealed a much higher incidence of multiple areas of brain injury or damage in people with untreated sleep apnea compared with normals. MRIs in people with sleep apnea show many more areas of "lacunar infarcts," or small areas of strokes. Rats with the Alzheimer’s gene that were subjected to chronic hypoxia were found on autopsy studies to have very similar histologic findings as in humans with Alzheimer’s. We also know that chronic hypoxia and inflammatory state that results from sleep apnea can cause microscopic areas of blood vessel clotting (rather than your more typical large vessel stroke). The authors of some of these studies were very careful in only alluding to the implications of their findings: That obstructive sleep apnea can lead to Alzhiemer’s. 

 

I’m not discrediting all the great research out there on Alzheimer’s, but at least consider the possibility that in some cases of Alzheimer’s, untreated obstructive sleep apnea can lead to Alzheimer’s, with the same clinical symptoms, biochemical and histological changes that are seen in classic Alzheimer’s patients. 

 

Mr. Moran is more likely to know about his future health if he screens himself for obstructive sleep apnea, rather than undergo genetic testing for Alzheimer’s. At least there’s something you can do about sleep apnea.

 

(See related article by guest columnist Dr. Mack Jones.)

 

 

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