In a discovery that’s shaking up what we thought we knew about human blood, researchers from the University of Cambridge, Mahidol University in Thailand, and global hematology centers have identified a hybrid blood type so rare that it’s only been found in three people out of over 544,000 samples. Known as the B(A) phenotype, this hybrid blood type features characteristics of both blood group B and group A, something previously thought to be impossible.
This groundbreaking finding doesn’t pose any danger to those who have it, but it’s opening a whole new field of questions in transfusion science, genetics, and immunology.
Table of Contents
Discovery
It all started with routine blood sample classifications. A team led by hematologist Janejira Kittivorapart from Mahidol University spotted something unusual. Among several group B samples, three of them showed tiny traces of antigen A. That shouldn’t be possible under current medical understanding.
Normally, if someone has blood type B, they have B antigens on their red blood cells—but no A antigens. But in these three people, something weird happened: their red blood cells carried small, nearly invisible amounts of A antigen, too.
That’s when the team realized they were staring at something new: a genetic mutation in the ABO gene had caused this rare hybrid blood type.
How It Works
To know how rare and fascinating this is, we need a quick refresher on the ABO blood system.
Your blood type is determined by antigens—small molecules on the surface of red blood cells. These are built by enzymes that are coded by the ABO gene.
- Type A blood has A antigens.
- Type B blood has B antigens.
- Type AB has both.
- Type O has none.
So, a person with type B blood should never have A antigens. But these three people do—just in microscopic amounts. Researchers have named this hybrid type the B(A) phenotype, and it’s likely caused by rare mutations that affect the enzyme responsible for antigen production.
How Rare Is It?
Very. Out of more than 544,000 blood samples analyzed across multiple blood centers and hospitals, only three showed this hybrid blood behavior. That’s just 0.00055% of all tested samples—making it one of the rarest blood phenotypes ever recorded.
| Blood Type | % of Total Samples (Approx.) |
|---|---|
| O | 45% |
| A | 40% |
| B | 11% |
| AB | 4% |
| Hybrid B(A) | 0.00055% (3 out of 544,000) |
What’s the Risk?
For daily life? None at all. People with this hybrid type are completely healthy and live normal lives. But the issue arises during blood transfusions or organ transplants. If labs don’t recognize this hybrid trait, there could be compatibility errors that lead to transfusion reactions or misdiagnosed conditions.
This is why the finding is getting serious attention in hematology and immunology circles. Medical professionals may need to fine-tune how they classify blood types, especially in rare or confusing cases.
Why It Matters
The discovery hints that there may be more unknown variants of blood out there. This could influence:
- Transfusion compatibility protocols
- Autoimmune and immune system research
- Genetic evolution studies
The researchers found four distinct mutations in the ABO gene that appear to alter how the enzyme creates antigens. But the exact mechanism is still under investigation. What’s clear is that our understanding of blood isn’t as “complete” as we once thought.
Under Investigation
So, is this just a scientific curiosity? Far from it. Understanding rare blood phenotypes can help improve:
- Blood safety in hospitals
- Precision medicine
- Genetic mapping and ancestry studies
For now, researchers are urging labs and hospitals to be more aware of blood subtypes and update testing protocols to avoid confusion in the future.
This breakthrough reminds us that science is never finished—just when we think we know everything, a microscopic clue opens a whole new field of research.
FAQs
What is the B(A) blood phenotype?
A rare hybrid blood type with B antigens and traces of A antigens.
How many people have B(A) blood?
Only 3 out of 544,000 tested samples had it.
Is it dangerous to have B(A) blood?
No, it doesn’t affect health but can complicate transfusions.
What causes this rare blood type?
Specific mutations in the ABO gene change antigen expression.
Why is this discovery important?
It changes how we understand blood and improves transfusion safety.
