what is rhd
RHD (gene) Rh blood group, D antigen also known as Rh polypeptide 1 (RhPI) or cluster of differentiation 240D (CD240D) is a protein that in humans is encoded by the RHD gene. The RHD gene codes for the RhD erythrocyte membrane protein that is the Rh factor antigen of the Rh blood group system. RHD has sequence similarity to RHCE, RhAG, RhBG, and RhCG and these five genes constitute the Rh family.