When I searched up "Delacourt Harris Vuitton disease", I got hits for Lewy Body Dementia because Google is borderline worthless. When I put "Delacourt Harris Vuitton" in quotes, I got one hit for a garbage website.
In light of that, I'm left to wonder: whose idea was it to name this plot disease like it was a merger apparel brand?
I mean, I just assumed (apparently correctly, although it could be a transliteration issue) that it was a made-up name for the series' sake (especially with the "rare disease discovered 20 years ago" line, which reads to me as "I, the author, am not comfortable using a real disease, have a Generic Protagonist Disease instead" which, to be fair, is arguably better than picking a real disease and then risking misinforming everyone about its effects because you screwed up your amateur research.)
But man. It totally broke my suspension of belief so hard. MC dying of Luxury Handbag Disease...!
...Interestingly, Wikipedia tells me (accurately or no) that the corruption of the name "De la cour" to the name "Delacourt" can be traced to a single person at a single point in history.