Six new gene variants that increase Alzheimer's disease risk

In Beating the Dementia Monster, we noted that variants of three genes can nearly guarantee that someone with one of the variants will develop young-onset (or early-onset) Alzheimer's disease.  These are for the amyloid precursor protein (APP) on chromosome 21, presenilin 1 (PSEN1) on chromosome 14, and presenilin 2 (PSEN2) on chromosome 1.  When these genes work properly, the APP protein is chopped up into water soluble fragments.  When their variants don't work correctly, the fragments are different, and they don't dissolve.  Instead, they accumulate on neurons as plaques and apparently kill the neurons.  People with these variants may develop the disease when they are in their thirties, forties, or fifties.  

But few people have these gene variants.  Some estimate that they exist in as few as 300 families around the world.

Then there is the APOE4 variant of the apolipoprotein E (APOE) gene on chromosome 19.  The APOE gene describes a protein that assists in the transport of cholesterol in the blood.  This variant, APOE4, does not guarantee you will get Alzheimer's disease, but it significantly increases your risk -- especially if your genome carries more than one copy.  Consumer genetic testing services, like 23andMe, look specifically for the APOE4 variant to describe your genetic risk for Alzheimer's disease.

However, as we noted in Beating the Dementia Monster, researchers have identified as many as 30 other genes that also increase your risk of Alzheimer's disease.  In most cases, they predispose the brain for inflammation, an important mechanism in the advance of the disease.  Researchers have been scouring the human genome to find them all, but perhaps 40% of our DNA remains to be evaluated.  So there are almost certainly more to be found. 

Six more turned up recently.  In research published in Alzheimer's and Dementia, the Journal of the Alzheimer's Association, researchers from the University of Kentucky claimed to have identified the six new genes, in addition to confirming five previously identified.  

Apparently, these genes are relatively rare.  Researchers found them by studying the genomes of members of several families in Utah, identified using the Utah Population Database.  In the database, researchers have been able to identify families with various disease occurrences, including both cancers and Alzheimer's disease.  In the case of this research, they identified families predisposed to Alzheimer's disease, and they were then able to compare the genomes of various family members, looking for similarities and differences.  This way, they found correlations of specific genes with the appearance of Alzheimer's disease. 

If you learn that you have genes in your DNA that predispose you to Alzheimer's disease, what should you do?  Read Beating the Dementia Monster!  There are things you can do.  You can fight inflammation, you can fight oxidation, and you can rebuild brain tissue.  So just do it.