The Rh blood group system consists of 54 antigens carried on two proteins (RhD and RhCE) each consisting of 417 amino acids. Combinations (hybrids) between the two genes are not uncommon. The proteins consist of 12 membrane-spanning domains.
The Rh blood group system consists of 55 antigens. Many are encoded at the RHCE locus and a number are encoded by hybrid RHCE with RHD. The RhCE protein (CD240CE) consists of 12 membrane-spanning domains and 417 amino acids. The amino and carboxyl termini are predicted to be intracellular, and the initial methionine is cleaved post-translationally. The expression of Rh proteins requires functional RhAG proteins, predicted to form heterotrimers with Rh.