Here are two separate cases.
A chronic alcoholic stumbles into your emergency room, but as you take a history, you realize he has no idea who he is or where he is. He can't do serial 7's, doesn't remember any of three objects after a few minutes, can't copy a figure. His MMSE is pretty bad. On exam, you notice this:
He suddenly says, "Oh I remember what's been bothering me. I have to keep going to the bathroom. Must be something I ate."
Challenge 1: Is it something he ate? Or something he didn't eat? What's the diagnosis?
-You can see the changing posture of this boy over time. On exam, you notice he has huge calves. These days, though, he has to use his arms to push himself up from a sitting position.
Challenge 2: What's the mutated gene?
First image is in the public domain, second image shown under fair use.