Super-Rare ‘Hybrid’ Blood Type Identified in Three individuals
Researchers have discovered an exceptionally rare blood type, dubbed B(A), identified in just three out of nearly 550,000 blood samples analyzed. The finding, published in Transfusion and Apheresis Science, reveals a previously unreported genetic mutation affecting the ABO gene, which dictates blood type.
The study, prompted by discrepancies in routine blood typing, pinpointed four mutations in the ABO gene responsible for encoding the enzyme that adds sugar to blood cells. In these cases, the blood is technically type B, but exhibits a small amount of A antigen activity, leading to confusion during standard blood typing tests.
“Future studies are required to elucidate the structural and functional consequences of the mutated [enzyme] AB transferase,” the researchers concluded.
The rate of ABO discrepancy was significantly higher among patients receiving treatment for serious illness (171 samples,or 0.08 percent) compared to donors (74 samples, or 0.03 percent). Only two donors also presented with the B(A) phenotype.
This discovery highlights the potential for undiscovered blood variations and reinforces the importance of genetic testing when conventional methods yield inconclusive results.
The finding builds on recent breakthroughs in blood group identification. In 2024, scientists solved a 50-year mystery, identifying a new blood group system. Earlier this year, researchers in France identified what appears to be the world’s newest and rarest blood group, “Gwada-negative,” found in a single patient from Guadeloupe.
“She is undoubtedly the only known case in the world,” said medical biologist Thierry Peyrard from the French Blood Establishment. “She is the only person in the world who is compatible with herself.”
