Scientists identify genetic basis of AnWj blood group antigen, establishing MAL system

Researchers have identified the genetic basis of the AnWj blood group antigen, solving a puzzle that dates to its original description in 1972 and formally establishing a new blood group system designated MAL. The findings, reported by ScienceDaily drawing on primary research, show that variation in the MAL gene — encoding a proteolipid involved in membrane transport — determines whether the AnWj antigen is expressed on red blood cells.

AnWj-negative individuals are exceptionally rare, but when they require transfusion they are at risk of serious haemolytic reactions because compatible blood is extremely difficult to source. Prior to this work, the absence of a known genetic marker meant that identifying AnWj-negative donors and patients depended on laborious serological screening. A molecular test based on the MAL gene could substantially reduce that burden and improve safety for affected individuals.

The discovery extends the International Society of Blood Transfusion's catalogue of recognised blood group systems. For transfusion medicine services, the finding provides a framework for genotyping-based donor screening alongside existing systems such as ABO, Rh, and Kell. Researchers note that the MAL system joins a growing number of blood group loci resolved through genomic approaches, reflecting the broader utility of large-scale sequencing databases for rare antigen discovery.

The primary research source has not been individually identified in the feed item; the ScienceDaily write-up does not name the publishing journal or lead institution, so those details cannot be confirmed from available information.