A few years ago, I made a comment in a similar topic asking for more details, and I got a very good reply. Hat tip to tait:

> It's complicated.

> There are more than 35 red blood cell groups (see https://www.science.org.au/curious/people-medicine/blood-typ... for a nice writeup). For each of those blood groups, there is more than one possible configuration of some protein or carbohydrate (something like more than one possible genetic sequence leading to more than one kind of molecule on the surface of the RBCs).

> And, even with ABO, there can be infrequent variations that make things more complicated (see https://professionaleducation.blood.ca/en/transfusion/best-p... for more).

> For the other blood groups, I think every case the groups were identified because a patient somewhere made an antibody, causing either a transfusion reaction (if not tested ahead of time) or, more likely, a positive (incompatible) reaction on in compatibility testing.

> [...]

It's worth reading the full original comment because it has more interesting details https://news.ycombinator.com/item?id=33507052

There has been past coverage of the rare Rh-null "golden blood" type, which lacks all of the Rh family of antigens. Only 9 donors worldwide.

https://en.wikipedia.org/wiki/Rh_blood_group_system#Rhnull_p...

Kind of lacks details, at first thought I thought it was going to be about this type:

https://en.wikipedia.org/wiki/Hh_blood_group

Can O- be used for this new type ? I know group Hh the answer is no.

Deletions in the MAL gene result in loss of Mal protein, defining the rare inherited AnWj-negative blood group phenotype

https://pubmed.ncbi.nlm.nih.gov/39158068/

Does this article seem weirdly phrased in places to anyone else?

Like here:

> They identified the genetic background of the previously known AnWj blood group antigen, which was discovered in 1972 but unknown until now after this world-first test was developed.

That sentence feels ponderous and a bit ambiguous to me. How does the genetic background of the AnWj blood group antigen relate? And if it was known in 1972, what exactly did these researchers discover about it? Am I missing background knowledge, or am I just having a bad day for reading comprehension or something?

There was a bunch of talk years ago about synthetic type O blood able to be mass produced?

Any word on that?

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