New Blood Type MAL Discovered! What It Means for Rare Blood Types

Blood groups are classified into systems based on specific antigens present on red blood cells. Although the ABO and Rh systems are the best known, there are 47 blood group systems in total, covering over 360 antigens. Recent research led by NHS Blood and Transplant scientists has revealed a new blood group system, called MAL, which includes the AnWj antigen. Although this antigen was first identified in 1972, its genetic basis has only recently been understood.

Significance of the discovery

Dr Louise Tilley from NHS Blood and Transplant led the research into the MAL system, which was a major breakthrough. “The genetic background of AnWj has been a mystery for over 50 years,” Dr Tilley said. “Our team’s work to solve this was a major milestone, allowing us to provide better care for patients with rare blood groups.”

Impact on blood transfusion

The identification of the MAL system is crucial for patients who are AnWj negative. These individuals can have severe reactions if they receive AnWj positive blood. The new discovery makes it possible to create genotyping tests to identify these rare cases, thus reducing transfusion-related risks.

More than 99.9% of people are AnWj positive, with the Mal protein present on their red blood cells. People who lack this protein may have it for genetic reasons or specific health conditions.

Research methodology and findings

The research team, including Professor Ash Toye from the University of Bristol and Dr Nicole Thornton from NHS Blood and Transplant, used whole exome sequencing to identify deletions in the MAL gene that are associated with the AnWj-negative phenotype. “It is exciting to confirm the genetic basis of AnWj using cutting-edge gene manipulation techniques,” said Professor Toye.

Challenges and future implications

Dr Tim Satchwell from UWE Bristol highlighted the difficulty in identifying the MAL protein due to its small size and unique properties. This discovery is expected to improve the safety of blood transfusions and facilitate the identification of rare donors and patients, improving overall care.