Blood-type based dystopia.

In some Asian countries, such as Japan, there is a certain superstition (similar to zodiac signs) that says your blood type influences your personality and how you relate to others, people of certain blood types might go well while others dosen't.

Imagine if that were true, and not only that, but they also discover that people of a certain blood type are prone to being "criminals," which starts a persecutuon agaisnt them and eventually a blood-type based dystopia where your blood type actually change how you are treated and your position in society.