A couple of things I saw

I try to scan various neurology and Alzheimer's disease journals looking for interesting news to share.  Most of them cost several hundred dollars for a subscription, but all have synopses of their content.  Most will occasionally offer interesting material for free, but not often enough.  The going rate to purchase a single article is $30.  Unfortunately, the synopses usually include just enough information to pique your interest, but without a punch line.  And, as I've mentioned before, the volume of research news has been throttled by covid-19.  Nevertheless, here are a couple of interesting tidbits I came across, although I didn't always have enough access to fill in all the blanks:

• JAMA Neurology (JAMA used to be Journal of the American Medical Association) included an editorial on blood tests for Alzheimer's disease.  Apparently there is anticipation that consumer kits will be available for these tests.  So far, the tests aren't yet available to medical professionals, but they seem to be candidates for something you can do in your home.  The opening lines of the editorial expressed ethical concerns about this, possibly due to concerns that people may have trouble understanding the implications of they resulsts they are getting from the test.
• An article in Neurology, the Journal of the American Academy of Neurology, examined the relationship between sleep, major depressive disorders in older people, and a diagnosis of Alzheimer's disease.  They found that Alzheimer's disease may influence sleep patterns.  (I'm not sure what the news is there.)  However, they did not find evidence supporting a causal role of disturbed sleep patterns for AD or evidence for a causal relationship between major depressive disorders and Alzheimer's disease.  Both of the latter conflict with other things I've read, although the distinction may be dissociating cause from correlation.  But they also associated genetically-based "being a morning person" with a higher risk of Alzheimer's disease and found an inverse correlation between risk of insomnia and risk of developing Alzheimer's disease.  These findings appears to conflict with other research of read on these topics.  For example, there seems to be evidence elsewhere for a correlation between depression and Alzheimer's disease.  They did not seem to reconcile their novel results with other research.  However, they may be more focused on looking for causal relationships rather than than the simple correlations identified by others.
  
• An article in ALZForum discussed the discovery of many new genes that both: 
• Promote development of Alzheimer's disease in people carrying the APOE2 gene variant (a gene normally not associated with Alzheimer's disease)
• Discourage development of Alzheimer's disease in people carrying the APOE4 gene (a gene strongly associated with Alzheimer's disease, at least in people of European ancestry).

So the genetic picture is more complicated than we previously thought.  We did say in Beating the Dementia Monster that having the APOE4 gene variant in your genome (in your personal DNA) is a risk factor for developing Alzheimer's disease, but it does not guarantee that you will get it.  We also said that there are other genes that can promote Alzheimer's disease, usually by promoting inflammation.  We have also noted that the "normal" form of the APOE gene is #2, which we will often write as APOE2, or ApoE2.  The purpose of the gene is to describe a protein used to transport cholesterol in the blood stream.

 

According to 23&Me, I do not carry the APOE4 gene variant, but I still developed Alzheimer's disease.  So, if you follow the genetic model for understanding how the disease develops, these other new genes might explain why I have it anyway. 

 

The old biology teacher in me wants to call the variants "alleles," which is the correct term.  That wouldn't be hard for you regular readers to follow, but I don't want to confuse the casual visitor with unfamiliar terminology.