A Joker Story - "Definitive Therapy" was commissioned and paid for by DC Comics for an anthology called The Further Adventures of The Joker to tie in with the first Batman movie.
Two twins were born from a Rich Father and a very poor mother. An altercation happened and they ended up splitting at a young age not remembering a thing. The two meet up in High-school and learn about each other's lives. There lives go in a twist and changes them forever.