Phenotypic Profile of Rh Blood Group Systems among Females of Child-Bearing Age in Pakistan

The Rh blood group system discovered in 1939 is only second in importance to the ABO system in terms of transfusion [1]. It is a highly complex blood group system with more than fifty different antigens [2]. However, most clinical transfusion issues are associated with the five principal antigens D, C, c, E and e. Rh antigens are non-glycosylated proteins in the RBC membrane [3]. Two closely linked genes on chromosome 1 control the expression of Rh; one gene RhD codes for the presence of RhD, and a second gene codes for the expression of CcEe antigens [4]. The Rh antigens are thought to play a role in maintaining the integrity of the RBC membrane. They may also be involved in transport of ammonium across the RBC membrane [5].