How can a person be blood type AB and display both types of processed antigens if the ABO gene allelic variant

This disease would be more common in the males than in the females, all female offspring of an affected male with a   normal female  would be carriers, there would be a 50% chance of a carrier woman to give birth to an affected male and all males born to an affected female would be affected even if the disease is recessive since males only have one copy of the x chromosome.