Rhnull individuals have no Rh antigens (no Rh or RhAG) on their red blood cells.[43] This condition is rare.[43] As a consequence of Rh antigen absence, Rhnull red blood cells also lack LW and Fy5 and show weak expression of S, s, and U antigens. Red blood cells lacking Rh/RhAG proteins have structural abnormalities (such as stomatocytosis) and cell membrane defects that can result in hemolytic anemia.[31][43]