Genetic basis of rare blood group variants

A transfusion of donor red blood cells can be life saving In individuals with massive blood loss due to an accident or surgery or in individuals with constitutive anemia due to a defect in erythropoiesis. Donor blood can, however, not be simply transfused to every patient. When a recipient of a red blood cell transfusion has an antibody to a blood group antigen present on the surface of the transfused donor red blood cells, the recipient’s immune system can destroy all donor red blood cells resulting in a sometimes fatal transfusion reaction. Consequently, it is very important to transfuse compatible donor red blood cells. At this moment blood group antigen status is determined via serology, but serology is sometimes inconvenient or not possible. Genotyping of blood group antigens can replace serology. To correctly genotype blood group antigen status the genetic basis of a blood group and the effect of genetic variation in blood group alleles must be known. We determined that negativity of the Vel blood group is caused by a deletion in the SMIM1 gene. Furthermore, we determined the quantitative and qualitative effect of genetic variation on antigen expression of the RhD, Kidd, JRA, LAN and Vel blood group systems. Finally, the developed blood group genotyping assay can correctly determine the status of almost all blood group antigens. In conclusion, when genotyping of blood group antigens replaces serology blood transfusions can be better adjusted between donor and recipient and the amount of (fatal) transfusion reactions will be further diminished.