New MAL Blood Group System Identified, Revealing Genetic Basis of Rare Blood Types

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

Significance of the Discovery

Dr. Louise Tilley from NHS Blood and Transplant spearheaded the research on the MAL system, marking a significant breakthrough. "The genetic background of AnWj has been a mystery for over 50 years," noted Dr. Tilley. "Our team's work to resolve this has been a major milestone, enabling us to offer improved care for patients with rare blood types."

Impact on Blood Transfusion

The identification of the MAL system is crucial for patients who are AnWj-negative. These individuals can suffer severe reactions if given AnWj-positive blood. The new discovery allows for the creation of genotyping tests to identify these rare cases, thereby reducing transfusion-related risks.

Over 99.9% of people are AnWj-positive, with the Mal protein present on their red blood cells. Those who lack this protein may do so due to 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 associated with the AnWj-negative phenotype. "It's exciting to confirm AnWj's genetic basis using advanced 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 blood transfusion safety and facilitate the identification of rare donors and patients, enhancing overall care.