Occurrence of Rare Deletional Yus and Gerbich Alleles in Syria and Neighbouring Countries.

Background: Gerbich-negative phenotypes of the Gerbich Blood Group System (ISBT 020) are very rare (with the exception of Papua New Guinea). The Gerbich-negative phenotypes Yus and Gerbich are negative for the antigens Ge2, and Ge2 and Ge3, respectively. In antigen-negative individuals, anti-Ge2 and anti-Ge3 antibodies can be naturally occurring, or are triggered during pregnancies and after transfusions. Previous studies suggested an elevated frequency of Gerbich-negative phenotypes for the Middle East. In the summer of 2015, a large-scale migration of people from the Middle East to Europe occurred raising the issue of question how to guarantee blood supply for patients and manage antenatal care for pregnant women from these countries.

Materials And Methods: To investigate the frequency of rare Gerbich-negative phenotypes, 1,665 immigrants to Germany originating from the Middle East were genetically tested for the presence of rare Yus, i.e., *, and Gerbich, i.e., *, alleles and compared to results obtained from 507 Germans.

Results: Seven Yus * and one Gerbich * alleles were exclusively observed among people from the Middle East, with five of them clustering among 797 Syrians. No such alleles were observed in Germans. A cumulative Yus- and *type allele frequency of 0.00314 and resultant overall Gerbich-negative phenotype frequency of one among 101,633 Syrians were calculated.

Conclusion: This manuscript describes for the first time an exclusively genetic screening for carriers of Gerbich-negative alleles. In conclusion, the Gerbich blood group system should be considered as one causative agent of unusual antibodies to red cell antigens, in routine patients and pregnant women, especially when originating from the Middle East.