A a mutant is a human being that possesses a genetic trait called the X-gene. It causes the mutant to develop superhuman powers that manifest at puberty. There are all types of mutants.
Then there is the Salvatore School for witches, werewolves and vampires.
Miss Robichaux's Academy as far as I know only accepts witches.
Then finally there is the Hogwarts School for witches and wizards.