Such antigens are termed as Rare blood group is a concern when blood transfusion is to be done on a regular basis, for example in patients with thalassemia, leukemia and other blood-related diseases, as well as certain emergencies like accidents, surgical complications, etc.
People with such rare blood groups are encouraged to indulge in regular blood donation so as to ensure timely help for a needy individual.
As of today, more than 30 blood type systems have been identified including ABO, Rhesus, MNS, Kell, Lewis, etc.
Before looking at some rare blood types, let us understand the basics about blood groups.
In rare cases, a complete lack of the glycophorin molecules (either one or both) occurs in a few individuals giving rise to three rare blood types.
The RBCs present in such individuals are naturally resistant to destruction by malarial parasites.
This gave birth to the ABO system for identifying blood types, and initiated a series of studies regarding other antigens present on RBCs.A2 is comparatively rare, whereas A3 is the rarest subgroup of A antigens, and is observed in less than 0.1% of individuals with A antigen.The occurrence of A2 subgroup is rare in the Asian population and hence A2 and A2B blood groups are the rare blood types amongst Asians.Rare blood groups under the common blood group systems have been listed below.
These systems of blood typing depend on a set of carbohydrate antigens called A, B and O antigens as well as the rhesus factor or D antigen.
The precise set of antigens for an individual is a result of the combination of genes inherited from the parents.