Doctors Detected a Mysterious Antibody in a French Woman's Body. It Turned Out to Be a Brand New Blood Type

[Judi Lynn]

Called “Gwada negative,” it marks the discovery of the 48th known blood group system in humans

Sarah Kuta - Daily Correspondent
June 24, 2025

In 2011, a French woman was undergoing routine medical testing before surgery when doctors discovered a mysterious antibody in her blood.

Now, scientists say the woman is the only known carrier of a new blood type called “Gwada negative.” It’s the only blood type within a new blood group system that scientists have dubbed “PigZ,” which is now the 48th known blood group system in humans, as the French Blood Establishment (EFS) announced last week.

The woman, who has not been identified publicly, is from Guadeloupe, a French-controlled island group in the Caribbean. When the woman had her blood drawn nearly 15 years ago, she was 54 years old and living in Paris. At the time, doctors knew something was unusual about her blood, but they didn’t have the resources to investigate further.

In 2019, researchers revisited the case. After requesting additional blood samples, they sequenced the woman’s entire genome, which contained approximately 22,000 genes. Her DNA revealed that she had a genetic mutation, which she inherited from both of her parents, that resulted in a previously unknown blood type.

“She is the only person in the world who is compatible with herself,” says Thierry Peyrard, a biologist with the EFS, to the Agence France-Presse (AFP).

The name “Gwada negative” comes from the phonetic pronunciation of Guadeloupe, the woman’s home region. It “sounds good in all languages,” Peyrard tells the AFP, and so far has been a popular name among experts.

More:
https://www.smithsonianmag.com/smart-news/doctors-detected-a-mysterious-antibody-in-a-french-womans-body-it-turned-out-to-be-a-brand-new-blood-type-180986866/