Rh null, often called the “golden blood type,” is considered the rarest blood type in the world. It is estimated that about 1 in every 6 million people may have this blood type, but fewer than 50 individuals have been identified globally.
There are 56 proteins that can determine a person’s Rh factor. However, blood is usually classified as either Rh positive or Rh negative based only on the presence or absence of one protein, known as the D protein.
Rh null is unique because it does not contain any of the proteins that define the Rh system in red blood cells. This results from a genetic mutation and leads to a condition known as Rh deficiency syndrome.
Main blood types
The main blood types are A, B, AB, and O, and each can be classified as either Rh positive or Rh negative. These classifications are the most commonly used, especially because they are critical when determining compatibility for blood transfusions.