An update on the JR blood group system

This update of the JR blood group system (Castilho L, Reid MR. A review of the JR blood group system. Immunohematology 2013;29:63–8) reports new ABCG2 alleles encoding Jr(a–) and Jr(a+^w/–) phenotypes, the predominant alleles encoding the Jr(a–) phenotype, and new functional aspects of the ABCG2 glycoprotein. The JR blood group system (International Society of Blood Transfusion system 32) consists of one antigen: Jr^a.