Nope! From Sphynxes to Snowshoes, ManyPets covers any and all domesticated cat breeds. And ManyPets won’t exclude treatment for new conditions that are common to your kitten’s breed just because they’re hereditary.
If your cat’s breed does suffer from common hereditary illnesses, it makes all the more sense to insure your pet before those conditions are diagnosed or symptomatic and become pre-existing. Do be aware that, if your cat’s breed is particularly prone to health conditions, this may factor into higher premiums.