ApropoE4, great point. I also wondered about this from an epidemiological perspective. From what I’ve learned, the geographic specific presentation wouldn’t necessarily appear as not
everyone is susceptible. This appears to be a case of specific genetic predisposition (about 1/4 of HLA-DQ/DR haplotypes) intersecting with exposure to mycotoxins that results in what Dr. Bredesen is calling Inhalational AD.
Since the majority of patients with CIRS have a combination of genetic sensitivity plus exposure to a complex aerosolic mixture of mycotoxins, spores, bacteria, microbial fragments, inflammagens, volatile organic compounds, and other molecular species, the majority of patients with type 3 Alzheimer’s disease and CIRS are likely to have an inhalational cause of Alzheimer’s disease (IAD).
Those who carry the HLA-DQ/DR haplotype and also exhibit a specific constellation of chronic inflammatory response syndrome/CIRS symptoms and laboratory abnormalities are suspect. The paper also points out that there are other known causes of CIRS such as biotoxins, from the Borrelia burgdorferi of Lyme disease or from other tick-borne pathogens, or aquatoxins such as those from dinoflagellates. Wild speculation on my part, but I wonder if there are OTHER as yet unidentified causes (lectins, other dietary sensitivities, viruses, etc.) that can also result in a CIRS presentation in those who are genetically predisposed.
Dr. Bredesen was very interested to learn that many of us exhibit mast cell activation/MCA symptoms that overlap with CIRS symptoms. Because I have BOTH a history of MCA and an innate immune dysfunction (hypogammaglobulinemia,) he’s recommending that I have the following labs run to see if I fall into the susceptible category:
HLA-DR/DQ: LabCorp code 167120
TGF-beta-1: Quest code 52112
MSH: LabCorp code 010421
NJC-C4a: Quest code 42658
Dr. Bredesen suggests that anyone with MCA or CIRS symptoms have the above tests run. Apparently those who carry this genetic susceptibility are predisposed to not only Type 3,
but ALL all of the subtypes he’s identified 
. I find it fascinating that Ehler-Danlos Syndrome/EDS folks (like me) have been found to carry a version of the HLA-DQ/DR haplotype. I’m struggling to wrap my head around Dr. Bredesen's description of this evolving clinical presentation that he’s repeatedly encountering. I agree with his analysis that at some point things are more than chance or coincidence.
Coincidentally, Chris Kresser recently shared that his family was exhibiting symptoms of mycotoxin exposure. He just did a podcast on getting your house tested for mold and other mycotoxins. Here’s a link to both the podcast & transcript:
http://chriskresser.com/how-to-test-you ... f45c32283b