Gwada Negative: The 48th Human Blood Group and an Extraordinary Genetic Discovery

In 2011, doctors preparing a woman from Guadeloupe for a routine surgical procedure made a discovery that would later transform global blood science. During standard pre-operative testing, her blood reacted in a way that did not match any known blood group within the 47 established human blood group systems. The unusual reactions immediately drew the attention of hematologists, raising questions no one had ever asked before.

Years later, in 2019, researchers conducted advanced genome sequencing to understand the cause of these unexplained results. Their analysis revealed a rare mutation in the PIGZ gene, a gene involved in producing certain surface structures on red blood cells. This mutation created a completely new antigen, unlike any previously documented in medical literature. As a result, scientists officially identified a brand-new blood type.

This newly discovered blood type was named “Gwada negative,” inspired by the local nickname “Gwada” commonly used for Guadeloupe. More than just a rare variant, it is now officially recognized as the 48th human blood group system by international standards—making it one of the most significant blood discoveries in recent decades.

What makes this case even more remarkable is its medical implication:
No other donor in the world has been found to match her blood.
Every blood sample tested—whether from unrelated donors or even close family members—triggered an immune reaction. This means she is, at present, only compatible with her own blood for transfusions. In any serious medical situation where she might need emergency surgery or treatment, this poses tremendous challenges for doctors and blood banks.

The identification of the Gwada negative group is considered a groundbreaking milestone because recognizing extremely rare blood types is essential for safe transfusion medicine, advanced genetic research, and personalized healthcare. With global mobility and increasingly complex medical treatments, knowing these rare variations helps prevent dangerous transfusion reactions and improves patient outcomes.

Researchers are now working to determine whether other individuals around the world may carry the same PIGZ mutation. Discovering additional carriers would not only deepen scientific understanding but could also provide vital clinical support if the original patient ever needs blood in an emergency. Until such individuals are found, however, she remains one of the most genetically unique patients ever documented, highlighting just how diverse—and still mysterious—human genetics can be.

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Trusted Sources

(These are reputable organizations and media outlets that have publicly reported on or confirmed the discovery.)

• International Society of Blood Transfusion (ISBT) – responsible for classifying global blood group systems.

• Établissement Français du Sang (EFS) – France’s national blood authority that contributed to the research.

• Scientific American – covered the scientific explanation of the PIGZ mutation and antigen discovery.

• Smithsonian Magazine – reported on the medical and genetic significance of the new blood type.

• CBS News – published a detailed report on the woman with the unique Gwada negative blood type.

• AABB (Association for the Advancement of Blood & Biotherapies) – recognized and documented the newly identified blood group.