Even Crohn’s has different subtypes that are suspected to explain why different Crohn’s patients respond differently to the same treatments. Much like the comment about lupus. Crohn’s also is much more complicated than the general public is aware.
For example, it is well established that there is a subset of people with Crohn’s disease who go into remission while taking an antidepressant called bupropion and we have no idea why. No one believes this is because these people’s Crohn’s was caused by a psychological problem, but rather that the bupropion appears to have effects on the immune system that aren’t well understood. And this appears to only work in certain people. Do those people have a different “kind” of Crohn’s? Different underlying genetic response to bupropion? Those questions aren’t as easy to answer as you might think.