even cats that have been around for a long time have serious health problems, not just recently developed breeds. persians, siamese, maine coone cats...almost every purebred animal is prone to some problem or another. some are just more serious than others.
from what i was able to find online, the korat is prone to: respiratory tract infections; bad reactions to anesthesia, to pesticides and to vaccines; and a neurological disease called gangliosidosis (which breeders have been working hard to breed out of their lines).
i'm not trying to make you worry, i'm being helpful. not all vets know what every purebred animal might be prone to. for example, if you can go in and say "hey, i read that my cat might be prone to having a reaction to anesthesia. is there anything you can do to offset that?" then they will be able to take every precaution they know of to keep that from happening instead of putting them under anesthesia the standard way.