Scientists identify gene behind rare blood antigen, establishing new MAL blood group system

Scientists from NHS Blood and Transplant together with the University of Bristol have finally identified the gene that encodes the rare AnWj antigen on red blood cells, a mystery that has persisted since the antigen’s first description in 1972. Their work enabled the International Society of Blood Transfusion to list MAL as a distinct blood group system, assigning it the code ISBT 047 and marking it as the 47th system worldwide.

Because the AnWj-negative phenotype is extremely uncommon, the discovery offers a clearer pathway for locating compatible donors for affected patients. It also opens the possibility of genetic tests that can screen donors and recipients for this rare type. Researchers note that loss of the antigen can also result from certain blood disorders or cancers, not solely from genetic variation.