New ultra-rare blood type discovered in Guadeloupe woman

A groundbreaking discovery has added a new chapter to the science of human blood types. The International Society of Blood Transfusion (ISBT) has officially recognized a 48th human blood group, dubbed “Gwada negative,” named after the Caribbean island of Guadeloupe, where the patient who helped identify the type was born.

While most people are familiar with the basic ABO blood system — types A, B, AB, and O, along with the Rh factor — the reality is far more complex. Human blood contains more than 600 known antigens, and the combination of these markers can theoretically produce millions of different blood types. Yet, until recently, only 47 distinct blood group systems had been recognized by the ISBT.

According to a press release by the French Blood Establishment (EFS), the discovery of the new blood group began 15 years ago when a French woman of Guadeloupean descent gave blood during routine tests ahead of a surgical procedure. An unusual antibody was detected in her blood in 2011, but it wasn’t until 2019 that DNA sequencing pinpointed a specific genetic mutation as the cause.

“[This] is undoubtedly the only known case in the world,” said Thierry Peyrard, a medical biologist at EFS, in an interview with Agence France-Presse (AFP). “She is the only person in the world who is compatible with herself.”

The patient inherited the rare blood group from both of her parents, each carrying a copy of the mutated gene. Researchers named the new group “Gwada negative” in honor of her island homeland.

Understanding and identifying rare blood groups like Gwada negative is essential to improving patient care. Blood transfusions must be carefully matched to avoid immune reactions, where the body attacks unfamiliar antigens as foreign invaders — a response that can be life-threatening. While transfusions matched using the common ABO-Rh system have a 99.8% success rate, ultra-rare blood types still pose serious challenges.

“Discovering new blood groups means offering patients with rare blood a better level of care,” the EFS team noted.

The pace of discovery in this field has accelerated thanks to advancements in DNA sequencing. In fact, the 44th recognized blood group, “Er,” was only discovered in 2022, signaling that more unknown blood types may soon come to light.

As of now, “Gwada negative” stands alone — with just one person in the world known to have it — but researchers continue to search for others who may unknowingly share this rare genetic profile.

- Advertisement -