Scientists Identify a New Blood Group After a 50 Year Mystery

The Mystery That Started in 1972

It all began with a pregnant woman in 1972 whose blood baffled doctors. When her sample was analyzed, researchers noticed something strange it was missing a surface molecule that appeared on every other known red blood cell at the time. No one could explain it. Tests were run, hypotheses floated, but the absence didn’t fit into any known blood group system. Then, like many medical mysteries, it was filed away unsolved but not forgotten.

More than fifty years later, that forgotten puzzle has finally been cracked. A team of scientists from the UK and Israel has identified a new human blood group system, one that hid in plain sight for decades. Their work, published in 2024, adds an entirely new chapter to the story of how our blood defines us.

“It represents a huge achievement,” said Louise Tilley, a hematologist with the UK’s National Health Service. After nearly twenty years investigating this anomaly herself, she described the discovery as the culmination of a long, patient team effort one aimed at offering better care to rare but important patients who don’t fit the usual blood categories.

Beyond ABO: The Hidden Complexity of Blood

Most of us grow up knowing about the ABO system whether we’re type A, B, AB, or O and perhaps the Rh factor, the little “positive” or “negative” attached to it. But these are just the tip of the iceberg. Scientists have identified more than 40 blood group systems, each based on different proteins and sugars that coat red blood cells.

These molecules act like biological ID cards. They tell your immune system, “Hey, I belong here.” When the body sees unfamiliar ones like during a mismatched transfusion it can panic, attacking those foreign cells as if they were invaders. That’s why getting the right blood type in surgery or childbirth can literally mean the difference between life and death.

Most of the major blood group systems were mapped out in the early 20th century. But in recent years, scientists have found a few new ones hiding in plain sight, detectable only through advanced genetic testing. The Er system, for instance, was identified in 2022 and found in only a handful of people. The new blood group discovered by Tilley’s team follows a similar pattern extraordinarily rare, but medically significant.

Tracking Down the Missing Molecule

The search centered around a molecule called AnWj, present in over 99.9% of humans. That 1972 patient’s blood, however, lacked it entirely. The anomaly puzzled generations of hematologists. Why would one person’s red blood cells be missing a component seemingly essential to everyone else?

After years of genetic detective work, the researchers discovered the missing link: a small but critical protein known as MAL short for myelin and lymphocyte protein. This protein is found in both nerve and immune cells and plays a key role in keeping cell membranes stable.

When both copies of a person’s MAL gene carry certain mutations, the AnWj molecule never appears on the red blood cells. This creates what researchers now call the MAL blood group system and, in very rare cases, results in an AnWj negative blood type.

Interestingly, the team also found three patients who were AnWj negative without having MAL mutations. That suggested something else might be at play certain blood disorders can suppress the AnWj molecule temporarily. In other words, sometimes the absence isn’t genetic, but symptomatic of an underlying illness.

Decades of Frustrating Clues

Part of what made this discovery so difficult is that the MAL protein is incredibly small. “It’s a very small protein with some interesting properties,” said Tim Satchwell, a cell biologist at the University of the West of England. “That made it hard to pin down. We had to follow multiple leads at once before we could be sure we were looking at the right thing.”

The process was, in essence, a 50 year relay race. Early scientists handed down fragments of data and hypotheses that modern geneticists could finally test with precision tools. It took decades of cross referencing blood samples, sequencing DNA, and comparing patient histories to find a consistent pattern.

The eureka moment came when the researchers inserted a normal MAL gene into AnWj negative cells and the missing molecule reappeared. That was the final piece of proof: MAL was the source of the AnWj antigen all along.

A Closer Look at What MAL Actually Does

The MAL protein’s role goes beyond blood typing. It helps stabilize cell membranes and assists in transporting materials in and out of cells something fundamental to life at the microscopic level. Interestingly, researchers noticed that AnWj isn’t present in newborns. It shows up only after birth, suggesting that the MAL system “activates” as the body matures.

So far, no major diseases have been linked to the MAL mutation. The patients with this rare blood type don’t seem to suffer any ill effects. That said, identifying it matters deeply for transfusion medicine. AnWj negative individuals could have dangerous reactions if they receive blood from a typical donor.

Now that scientists understand the genetics behind MAL, hospitals can test patients to see whether their AnWj absence is inherited or suppressed by illness. That distinction could reveal hidden conditions that might otherwise go unnoticed.

The Human Side of the Discovery

It’s easy to get lost in the technical details proteins, antigens, mutations but this discovery also carries a quiet human story. Somewhere, half a century ago, a pregnant woman’s routine test revealed something no one had ever seen. She probably never knew her blood sample would become a scientific milestone decades later.

For hematologists like Tilley, who spent much of her career tracing that mystery, the breakthrough represents not just a scientific victory but a personal one. Blood research rarely makes headlines, yet these subtle molecular differences can mean everything for patients who need transfusions, organ transplants, or complex medical care.

Why This Matters More Than It Seems

On the surface, finding a new blood group might sound like a minor footnote in medical history another name to memorize in a long list. But it’s far more significant than that. Each discovery like this refines our understanding of how human biology operates at its most fundamental level. It also improves patient safety in ways most of us never think about.

For example, rare blood groups like MAL are often underdiagnosed. When hospitals can’t match a donor perfectly, even subtle mismatches can trigger immune reactions. Knowing exactly why a blood type doesn’t fit standard classifications helps doctors anticipate and prevent these complications.

And there’s another, almost poetic aspect to it: the fact that we’re still discovering new blood systems in the 21st century tiny molecular quirks that eluded detection for decades is a reminder that our understanding of the human body is far from complete.

Fifty Years Later, an Answer at Last

The mystery that began with a single woman’s blood sample in 1972 has now been solved. What was once just an odd absence in a microscope slide has become the foundation of a brand new blood group system one that could one day save lives.

The discovery of the MAL blood group doesn’t just close a 50 year old case. It opens new doors in medicine, genetics, and transfusion science. And perhaps most beautifully, it shows that even in something as well studied as human blood, there are still secrets waiting to be found.

Open Your Mind!!!

Source: ScienceAlert

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