Top. Diagram of the conventionalRHDandRHCEgenes. The coding regions consist of 10 exons, depicted as white and grey boxes, respectively. Bottom. Diagram of some RH genes commonly found in African ethnic groups. Shown are the RHD-RHCE gene that encodes altered C antigen, some examples of RHD encoding partial D (DIII, DAU, and DAR), and some examples of RHCE with mutations encoding altered or partial e that often complicate transfusion in sickle cell patients.