I have been mulling over the thought that these were somehow connected. There are a lot of obvious ties between AD and PD, but there is increasing signs that ET can be neurodegenerative as well. In addition to tremor, some patients develop gait problems, experience mood disorders, have signs of brain inflammation, some have Lewy bodies, and cognitive impairment. Further connections include a study showing people diagnosed with ET are 4 times more likely to develop PD. There is now also a genetic mutation connecting ET to PD known as LINGO1.

Epidemiological studies continue to surface showing familial aggregation of the three disorders. I am citing two articles and posting conclusion of each.
Then following with microbial part.


Familial associations of Alzheimer disease and essential tremor with Parkinson disease.

Our study suggests a familial susceptibility to AD amongst first-degree relatives of younger onset PD cases.

Association between essential tremor and other neurodegenerative diseases: what is the epidemiological evidence?

There is reasonable epidemiological evidence to support a link between ET and these neurodegenerative diseases. Further studies are needed to corroborate the current results, provide additional estimates of effect and begin to explore the mechanistic underpinnings for these intriguing associations.

Finally, I am wondering if all (at least AD and PD) are not result of microbial infection starting in our stomachs? Girija's recent post supports this plus it is already known that one of main AD proteins is an antimicrobial. Now we have further proof that PD is autoimmune. The LRRK2 mutation now linked to Chrone's and Leprosy:


Parkinson's disease-linked LRRK2 is expressed in circulating and tissue immune cells and upregulated following recognition of microbial structures



In looking at Girija's post on biomarkers, PWP have presence of tau and amyloid B14 in spine fluid. As the amyloid is considered antimicrobial in AD, why would it be anything else in PD?

Why aren't AD and PD studied together ever? We could be so much closer to a cure by restructuring the research paradigm and making sure that research efforts are better funded on a continuum toward proving or disproving a hypothesis and then following through. We will go nowhere unless this changes.

Any other thoughts on the connections? What else could it be besides infection?

I would like to know nutrient deficits of both ET and AD, this further supports the idea we all begin with a bacterial infection and possibly a dysregulated immune response?

Interesting possibilities...

Laura