AB- NEGATIVE

AB-negative is already one of the rarest common types, found in less than 1% of people. But the true rarest blood type in the world is RH-null, nicknamed Golden Blood because it lacks all 61 possible antigens in the RH system. Fewer than 50 people on Earth are known to have it. And it's so rare that it can only be received from another RH-null donor, making it both incredibly science and incredibly risky for the people who carry it. Since in an emergency, there may be no compatible blood available anywhere in the world. On skin, albinism causes near total lack of melanin, resulting in very pale skin, hair, and eyes. It affects about 1 in 20,000 people. But rarer, piebaldism, a condition where from birth, patches of skin and hair have no pigment at all, creating permanent white patches, most commonly a white forelock that contrasts sharply against normal pigmentation. Unlike vitiligo, which develops later in life and can spread, piebaldism patches are there the moment you're born, a fixed size and shape for life. Come from a mutation that stops pigment migrating areas of skin during development. On arms, polydactyly of the hand is well known, but having an extra arm level of rare. Polymelia is a congenital condition where a person is born with one or more supernumerary limbs. And it's so exceptionally rare that only a handful of documented cases exist worldwide. In most cases, the extra limb is attached near the shoulder or hip and has little to no function, so it's usually removed surgically shortly after birth. In extremely rare cases, however, the extra limb is functional enough that the person can move or even use it, which is part of why these cases get so much medical attention when they appear. Moving on: fingers. Polydactyly of the hand is well known, but having an extra arm level of rare. Polymelia is a congenital condition where a person is born with one or more supernumerary limbs. And it's so exceptionally rare that only a handful of documented cases exist worldwide. In most cases, the extra limb is attached near the shoulder or hip and has little to no function, so it's usually removed surgically shortly after birth. In extremely rare cases, however, the extra limb is functional enough that the person can move or even use it, which is part of why these cases get so much medical attention when they appear.