In 1972, a pregnant woman’s blood sample puzzled scientists when it lacked a surface molecule present on all known red blood cells.
Over 50 years later, UK and Israeli researchers identified a new human blood group, published in 2024.
A Breakthrough Decades in the Making
“This milestone crowns years of collaboration,” said NHS hematologist Louise Tilley, who dedicated nearly two decades to solving the mystery. “It allows us to provide better care for rare but significant patients.”
Watch the video below for a summary of their discovery:
Most people know the ABO and Rh systems, but many other blood groups exist, defined by different proteins and sugars on red blood cells.
Our bodies use these antigen molecules, among other functions, as identification markers to distinguish between our own cells and potentially harmful foreign ones.
If these markers don’t align during a blood transfusion, the procedure meant to save a life can trigger severe reactions or even be deadly.
Researchers discovered most major blood groups in the early 20th century.
Discoveries Few and Far Between
Researchers have recently identified blood groups like the Er system in 2022, found in only a few individuals — just like this newly discovered group.
“Tilley explained that studying such rare genetic cases made the research challenging.”
Earlier studies showed that over 99.9% of people have the AnWj antigen missing from the 1972 patient’s blood. Researchers linked it to a myelin and lymphocyte protein and named it the MAL blood group.
People with mutations in both MAL gene copies have an AnWj-negative blood type, like the 1972 patient. Yet, Tilley’s team found three AnWj-negative cases without the mutation, suggesting some blood disorders can suppress the antigen.
Unraveling the Mystery of the MAL Protein
“MAL is a small, complex protein that was hard to identify, requiring multiple investigations to confirm,” said Tim Satchwell of the University of the West of England.
After decades of research, scientists confirmed the gene by adding a normal MAL gene to AnWj-negative cells, restoring the antigen.
The MAL protein is known to help maintain cell membrane stability and support cellular transport. Earlier studies also revealed that the AnWj antigen is absent in newborns but develops shortly after birth.
A Shared Mutation Without Other Health Effects
All AnWj-negative patients in the study shared the same mutation, but researchers found no link to other cellular abnormalities or diseases.
With MAL mutation markers identified, doctors can tell if an AnWj-negative type is inherited or caused by suppression, possibly signaling another condition.
Understanding rare blood variations is vital for better care and saving lives.
Read the original article on:Sciencealert