I can remember reading something about a few people in the world with blood types that are unique to them,or a few other people.
Is this just a urban myth or medical fact?
There is a very rare blood type called Bombay O that’s found in only a few families. I believe there used to be one here where I live. Basically these people lack the precursor substance on the red blood cells which the majority of other people have. Related to this they have antibodies to this precursor and can’t receive blood from anyone but another Bombay O. I don’t know the incidence of this blood type offhand, but it is quite low.
It looks like the Bombay O incidence is approximately one in one million in Europe according to this site. About one in ten thousand in India, where it was first discovered.
Here’s a more in-depth discussion of what it actually means if you’re interested.
There was that one episode of Good Times where JJ was found to have blood type “U-positive.”
Many jokes were made along these lines:
Doctor: “You have type U-negative blood.”
JJ: “You positive?”
Doctor: “No, U-negative.”
There are a lot more blood types out there than just the ABO and Rh+/- types we usually use. We don’t hear about them because they’re not as useful. But pretty much any protein or sugar moiety that’s expressed on the surface of red blood cells could be considered a “blood type.” Therefore, if you had a harmless mutation that changed any one of these, you could technically say that you had a unique blood type. For what it’s worth.