– with a question mark is simple: ChatGPT is a Valley Girl.
Now if you can hear that sentence in your head with the right upspeak -- rising inflection or pitch when you get to "in Rett or Alzheimer's disease?" -- it'll be just like ChatGPT is sitting across from you flicking the ends of her hair.
Edit: Investor2014 has a different explanation for the question mark; but I think mine is right.