Science

Researchers identify genetic cause behind 50-year-old human blood group mystery

ScienceDaily reports that scientists have identified the MAL gene as the basis for the AnWj blood group antigen.

Updated Sep 20, 2026 · 06:24 UTC1 reports

The short version

Researchers at NHS Blood and Transplant and the University of Bristol identified the MAL gene as the biological foundation of the AnWj antigen, solving a mystery dating to 1972.[ScienceDaily]
More than 99.9% of humans are AnWj-positive, making inherited or acquired AnWj-negative status extremely rare.[ScienceDaily]
The discovery allowed the International Society of Blood Transfusion to formally establish MAL as a distinct blood group system.[ScienceDaily]
Finding the responsible gene enables new genotyping tests to help safely match rare AnWj-negative patients during blood transfusions.[ScienceDaily]

Scientists traced the origin of the AnWj blood group antigen to the MAL gene using whole exome sequencing.[ScienceDaily]
Over 99.9% of the population carries the AnWj antigen on their red blood cells.[ScienceDaily]
Absence of the AnWj antigen can be inherited via homozygous deletions in MAL or acquired through hematological disorders and cancers.[ScienceDaily]
The research was led by NHS Blood and Transplant in Bristol alongside the University of Bristol.[ScienceDaily]

Full clinical implications for acquired anti-AnWj autoantibodies remain partially uncertain, as some patients receiving unmatched blood did not present expected transfusion reactions.[ScienceDaily]

Outlet counts describe coverage, not independent confirmation. Reports may share a wire service or original source.