The rarest blood in the world: how people with Rh factor zero live
The "golden" or Rh-zero blood type is the rarest on Earth. What makes it unique and why its owners cannot be called lucky.The Rh null blood group is characterized by the fact that it has no Rh factor proteins on the red blood cells. According to the latest data, there are fifty people living in the world with Rh null - "absent" Rh factor, which means that there are no antigens in their blood. In total, scientists have described 29 cases of this rare phenotype.
The problem of owners of "golden" blood is that there are almost no Rh null donors in the world - according to different data, from 9 to 11 people. Therefore, blood with Rh null factor is considered the most valuable in the world and it is called "golden".
What is blood type?
On the surface of our red blood cells there are proteins called antigens. The antigen present determines a person's blood type - A, B, O or AB. Each is divided into rhesus positive or rhesus negative. The Rh D (RhD) protein antigen on the surface of red blood cells determines whether a person has the Rh factor or not. A person with a Rh-negative blood type lacks only the RhD antigen, while a person with a "golden" blood type lacks all Rh antigens.
Why do some people have "golden" blood?
It is believed that "golden" blood resulted from a spontaneous change in the RHAG (Rh-associated glycoprotein) gene, which encodes a Rh-associated glycoprotein. This protein is essential for directing Rh antigens to the membrane of red blood cells. The RHAG mutation is often associated with a condition known as hereditary stomatocytosis. These individuals may have long-lasting, mild, hemolytic anemia and increased breakdown of red blood cells.
There are several factors that put a person at a higher risk of having "golden" blood:
- Inbreeding.
- Autosomal genes (abnormal genes that have disease traits that are passed from generation to generation).
- Alterations or complete deletion of certain genes, such as RHD and RHCE or RHAG.
Is it possible to donate "golden" blood?
Yes, because of the absence of antigens, Rh null-blood is considered a universal donor. It is excellent for transfusion because it lacks common antigens and can be transfused to anyone who needs it and without risk of complications. However, it is very difficult to find this type.
Conversely, rhesus null interferes with people who have it. If they need a transfusion, such patients will not be matched with blood that contains the Rh antigen. This will cause a transfusion reaction.
What other difficulties do the bearers of "golden" blood have?
People who are Rh-negative can suffer from:
Rh incompatibility during pregnancy. If the mother has Rh factor zero and the baby is Rh positive, the mother's blood can produce antibodies. These will attack the fetus and lead to miscarriage.
Hemolytic crisis. Several studies have shown that infection or sepsis in such people can trigger massive hemolysis, subsequent kidney failure and other complications.
Mild to moderate hemolytic anemia from birth, which leads to faster destruction of red blood cells. This can cause low hemoglobin levels and lead to pallor and fatigue.
Generally, until 1961, scientists around the world believed that all embryos with Rh blood factor zero died in the womb. It cannot be said that to be born with "golden" blood is to win the lottery. To have such a rare blood type is at least inconvenient. This feature only complicates a person's life.