Comment by dekhn

Sorry, I should have said: the preponderance of people with disease suffer from (a small number of) polygenic trait diseases, while if you sum up all the monogenic diseases, it's a smaller number of people with disease by far. You're correct that there are many monogenic diseases but the vast majority of them are extremely rare.

In short, if you solve a monogenic disease you help maybe 20-30 million worldwide (and then you have to solve other ones), if you solve CVD,type 2 diabets, hypertension- each of those is 500+M people. So in general, we would expect to have more impact with polygenic, although they tend to be far harder to treat because of the complexity.