Left banner image adapted from amyloidosis gross node, by Ed Uthman MD, Creative Commons license

Presidential Grossness

Left, normal brain.                    Right, Alzheimer's brain
from Wikimedia
For President's Day I'm going to deviate a little to discuss disease, specifically diseases Presidents of the United States have had. Usually we focus on the human body itself, and disease is often thought to be caused by an external force - but what if the disease IS the body?

Alzheimer's. You've heard of it. You might even know someone who has it. But did you know that it's caused by normal proteins in the brain?!

The most common risk factor for getting Alzheimer's disease is simply being old. Another is family history, which implies a genetic cause. Two proteins, which are encoded by genes, have been associated with Alzheimer's: beta-amyloid and tau protein. Beta-amyloid is a byproduct of another protein that's produced for brain function - it is normally eliminated by other cells. Tau forms part of a  microtubule that helps transport nutrients within the brain.

These proteins are normally found in the brain as their own separate entities (or in the case of tau, integrated into the microtubule structure). But sometimes, they decide to bind to one another, and more of each other, and its these aggregations that disrupt brain plasticity and neuron transmission. Beta amyloid plaques and neurofibrillary tangles are the hallmark finding on autopsy that confirms the diagnosis of Alzheimer's.

How do these aggregates occur? We don't know. And that is truly gross.

So, which President had this disease? Ronald Reagan.

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