Scientists Identify New Blood Group

When a pregnant woman had her blood sampled back in 1972, doctors discovered it was mysteriously missing a surface molecule found on all other known red blood cells at the time. 

After 50 years, this strange molecular absence finally led to researchers from the UK and Israel describing a new blood group system in humans. In September, the team published their paper on the discovery. 

Most major blood groups were identified early in the 20th century. Many discovered since, like the Er blood system first described by researchers in 2022, only impact a small number of people. This is also the case for the new blood group.

"The work was difficult because the genetic cases are very rare," explained Tilley.

Previous research found more than 99.9 percent of people have the AnWj antigen that was missing from the 1972 patient's blood. This antigen lives on a myelin and lymphocyte protein, leading the researchers to call the newly described system the MAL blood group. 

When someone has a mutated version of both copies of their MAL genes, they end up with an AnWj-negative blood type, like the pregnant patient. Tilley and team identified three patients with the rare blood type that didn't have this mutation, suggesting that sometimes blood disorders can also cause the antigen to be suppressed. 

The MAL protein is known to play a vital role in keeping cell membranes stable and aiding in cell transport. What's more, previous research found that the AnWj isn't actually present in newborn babies but appears soon after birth. 

Interestingly, all the AnWj-negative patients included in the study shared the same mutation. However, no other cell abnormalities or diseases were found to be associated with this mutation.

These rare blood quirks can have devastating impacts on patients, so the more of them we can understand, the more lives can be saved.

This research was published in Blood.