> I have a genetic disease that shows up in 4/100k people, so rare, but not that rare. Any sizable town has at least a few dozen people with my disease. If one

> I have a genetic disease that shows up in 4/100k people, so rare, but not that rare. Any sizable town has at least a few dozen people with my disease. If one in 25k people has the disease, you need a 1 million+ population for city to have a 40 (a lowball "few dozen") incidences of the disease, assuming random distribution. There's only 10 cities in the United States that fit that description* and only London is big enough in the UK. There will be only 100 or so the medium sized states of say Utah or Nevada Takes a lot more than a medium sized town and that sounds extremely rare condition to me. I come from a medium sized town. Given your numbers, there's a good chance there is no one in the town has this disease and i wouldn't expect any of the doctors to be knowledgeable about it. https://en.wikipedia.org/wiki/List_of_United_States_cities_by_population https://en.wikipedia.org/wiki/List_of_United_States_cities_b... https://en.wikipedia.org/wiki/List_of_largest_United_Kingdom_settlements_by_population https://en.wikipedia.org/wiki/List_of_largest_United_Kingdom...