Researchers identify new blood group MAL, ending 50-year search

Overview

Updated 1 hour ago

In 1972, blood taken from a pregnant woman showed red cells missing a surface marker every other person carried. No one could explain it. Fifty years later, researchers traced the cause to a gene called MAL, establishing a new human blood group system.

People with AnWj-negative blood can suffer fatal reactions if given incompatible blood in a transfusion. The discovery lets labs run a genetic test to find these rare patients and donors before a transfusion happens.

Why it matters

A new genetic test can identify the rare patients and donors whose blood would otherwise trigger a fatal transfusion reaction.

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Key Indicators

47th

Human blood group system

The MAL system is the 47th officially recognized by the International Society of Blood Transfusion.

99.9%

People who are AnWj-positive

AnWj-negative blood is extremely rare, and most cases come from illness rather than genetics.

Genetically AnWj-negative samples in the study

Only eight samples traced to inherited DNA appear in the paper, some from the same families.

50+ years

Time from first detection to genetic explanation

The AnWj antigen was found in 1972; the MAL gene was identified in 2024.

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

People Involved

Louise Tilley

Senior research scientist, NHS Blood and Transplant

Led the team that identified the MAL gene behind AnWj-negative blood

Nicole Thornton

Coauthor, NHS Blood and Transplant

Helped confirm the MAL gene and warned of transfusion risks for AnWj-negative patients

Unnamed 1972 patient

First known AnWj-negative person

Her case launched the 50-year search

Organizations Involved

NHS Blood and Transplant

UK national blood service

Led the research

The UK body that manages blood donation and transfusion, whose reference laboratory led the MAL discovery.

University of Bristol

Research university

Academic partner in the discovery

Provided the genetic sequencing and cell-biology expertise that confirmed the MAL gene's role.

International Society of Blood Transfusion

Medical standards body

Ratified MAL as an official blood group system

The international body that sets blood group nomenclature and rare-donor standards.

Timeline

1972 September 2026

4 events Latest: Yesterday

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September 2026
Discovery highlighted in new reporting
Latest Report

ScienceDaily featured the MAL discovery, emphasizing the new genetic test that identifies rare AnWj-negative patients and donors.
Yesterday
September 2024
MAL gene identified as the cause
Scientific publication

NHS Blood and Transplant and University of Bristol researchers published a paper in Blood linking the AnWj antigen to the MAL gene and establishing the 47th blood group system.
September 20th, 2024
2015
Original sample retested
Research

The 1970s patient's stored blood was retested and remained AnWj-negative, serving as a key reference for later research.
2015
1972
AnWj antigen first detected
Discovery

A pregnant woman's blood test revealed red cells missing the AnWj antigen, puzzling doctors who could not explain the absence.
1972

Scenarios

NHSBT adds MAL genotyping to routine blood screening

Likely Resolves by End of 2027

Discussed by: NHS Blood and Transplant researchers, who wrote that tests can be added to existing genotyping platforms

The International Blood Group Reference Laboratory already built a genetic test for the condition. The next step is folding MAL typing into the standard donor and patient screening panels that blood services run. That would identify AnWj-negative people before a transfusion rather than after a reaction.

Global rare-donor registry expands with AnWj-negative donors

Possible Resolves by Q2 2028

Discussed by: WIRED's analysis of Nicole Thornton's comments

Thornton said the new test makes it easier to find AnWj-negative people willing to donate blood for the few patients who need it. Rare-donor programs coordinated by the International Society of Blood Transfusion would log newly identified genetic cases. Each new donor shrinks the pool of patients dependent on a handful of known compatible units.

MAL suppression emerges as a cancer diagnostic marker

Possible Resolves by End of 2028

Discussed by: Researchers who observed that certain cancers suppress MAL expression

The team noted that some patients develop AnWj-negative blood because a cancer or blood disorder suppresses the MAL gene rather than because of inherited DNA. That link could make MAL expression useful in monitoring certain cancers. Research would need to show the suppression tracks with tumor activity over time.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

1939–1940

Rhesus (Rh) factor (1939–1940)

Karl Landsteiner, Alexander Wiener and Philip Levine identified the Rh factor after finding that blood from a rhesus monkey produced antibodies against human red cells. The work explained why some women's immune systems attacked their babies' red cells, causing hemolytic disease of the newborn, and why some transfusions failed.

Then

Rh testing became standard in pregnancy and transfusion within a decade.

Now

Rh remains the second most clinically important blood group after ABO, and anti-D prophylaxis now prevents most cases of hemolytic disease.

Why this matters now

Like the MAL discovery, Rh showed that matching blood beyond the ABO groups saves lives in transfusion medicine.

1950

Duffy blood group (1950)

The Duffy blood group was named in 1950 after a multiply-transfused hemophiliac patient whose blood produced a new antibody. Later research found that most people of West African descent lack Duffy antigens, and that this absence protects against a malaria parasite that uses the Duffy receptor to enter red cells.

Then

The discovery added Duffy to routine blood typing for transfusions.

Now

It explained malaria resistance in large populations and made Duffy a central tool in malaria biology.

Why this matters now

Duffy shows that a rare or absent blood antigen can carry real clinical weight across large populations, the same reason AnWj matters.

1951

Kidd blood group (1951)

In 1951, a woman named Mrs. Kidd gave birth to a baby with hemolytic disease caused by an antibody later named anti-Jka. Kidd antibodies became known for causing delayed, sometimes severe, transfusion reactions in patients who had been sensitized by earlier pregnancies or transfusions.

Then

Kidd typing was added to pre-transfusion testing.

Now

The case established that newly discovered antibodies should be treated as clinically significant until proven otherwise.

Why this matters now

Kidd is the classic example of a blood group discovered because it caused a bad reaction, the exact scenario the new MAL test now prevents.