I made a more detailed comment downthread, but in the pediatric rare disease world, ten years is generally considered a fairly typical amount of time before one

I made a more detailed comment downthread, but in the pediatric rare disease world, ten years is generally considered a fairly typical amount of time before one can finally get a diagnosis, and that's for diagnoses that are actually known/identifiable/understood. The easiest way to explain this is that doctors typically don't want to diagnose life-long conditions if they've never seen them before. So your family doctor will send you to an internist, who will send you to an internist at the local academic medical center, who sends you to three specialists at the same medical center, who don't know what it is. Then you get a referral to someone in another city who specializes in something someone thinks it might be – that guy has diagnosed 10 people with this rare disease. You fly out, and he says "nope, you're not it." Wash, rinse, cry, repeat.