Objectives: To study gene frequency of RhD in Saudis in Dammam region
and the common Rh phenotypes. Materials and methods: Seven thousand an
d ninety three blood samples from Saudi male blood donors were evaluat
ed for presence or absence of D antigen. D negative antigen samples we
re tested for Rh phenotypes. In addition, another group of 616 Rh posi
tive samples (416 Saudi male donors and 200 Saudi female OPD patients)
were tested for Rh phenotype. All tests were done in Regional Laborat
ory & Blood Bank, Dammam using standard antisera. Results: The frequen
cy of Rh negative blood group in Dammam region was found to be 9.18%.
The gene frequency for ''D'' was calculated as 0.7. Rh phenotypes pres
ent in decreasing order of frequency were R(1)r, (RR1)-R-1,R(0)r, R(2)
r, rr, (RR2)-R-1, (RR2)-R-2, (RR2)-R-1, r(1)r, (RRz)-R-z, (RRz)-R-2, r
'' r, r'r ''. Conclusion: Rh negative frequency is more than previous
ly reported. RO and Rz haplotypes are more common while r is less comm
on compared with white European population.