A 'new' low-incidence red cell antigen, WARR: unique to Native Americans?

Investigation of a mild case of hemolytic disease of the newborn has led to recognition of a 'new' low-incidence red cell antigen, WARR (ISBT No. 700.55). Data gleaned from two kindreds, both with Native American heritage, exclude WARR from the MNS, Lutheran, Lewis, Duffy, Kidd, Xg, Chido/Rodgers, Kx and Gerbich blood group systems. Serologic or genetic evidence suggests it is not part of the Kell or Yt systems.