There’s Only One Person In The World With This Blood Type

An incredibly rare genetic mutation has given rise to a brand new blood type which is currently thought to exist in just one person. Known as “Gwada negative”, the exceptional blood group was identified earlier this month in a French woman from the island of Guadeloupe, solving a mystery that had puzzled doctors since 2011, when they first spotted an unusual antibody in the patient’s plasma.

Blood types are defined by the presence or absence of specific antigens on the surface of red blood cells, with the most common blood group system known as ABO. Under this system, individuals are placed into either the A or B blood types depending on whether they have A or B antigens, or the O group if they have neither.

Each blood type can then be subdivided into either positive or negative according to whether or not a person possesses Rhesus (Rh) antigens. Yet A, B, and Rh are far from the only antigens found on red blood cells, and unusual configurations of these have led to the identification of dozens of rare blood types.

At present, the list of known antigens on red blood cells exceeds 365, and Gwada negative is now the 48th confirmed blood group. Announcing the discovery, Thierry Peyrard from the French Blood Establishment (EFS) explained that a “very unusual” antibody was found in the woman’s blood as she underwent routine tests while preparing for surgery in 2011.

At the time, resources did not allow for further research to be conducted, although scientists were eventually able to use high-throughput DNA sequencing to reveal a specific genetic mutation in 2019. "This discovery was officially recognized in early June in Milan by the International Society of Blood Transfusion (ISBT)," continued the EFS statement posted to LinkedIn.

The woman is thought to have inherited this mutation from both of her parents, making her “undoubtedly the only known case in the world,” according to Peyrard.

Understanding a person’s blood type is a life-or-death matter for doctors as some types are not compatible with one another, which means that patients receiving blood transfusions must only be given certain types. For instance, type A blood contains antibodies that destroy B antigens – and vice versa – so it’s vital to never mix these two blood types.

As for the newly-identified owner of Gwada negative blood, Peyrard told AFP that "she is the only person in the world who is compatible with herself.”