Two further examples of the low-frequency antigen Rea (Reid).

A positive direct antiglobulin reaction of a baby's cells, found during antenatal testing at Cardiff, was caused by a low-frequency antigen which has been identified as Rea (ISBT No. 700019). Investigations with this, only the second example, anti-Rea revealed another Re(a+) propositus in testing 6,635 random donors at Oxford; no further positive was found in 4,770 random donors at Cardiff. Study of the families of these two propositi, the first to be identified since the original Canadian family, confirmed that Rea was inherited as an autosomal Mendelian dominant. The families showed that Rea is not controlled by the ABO, Kell or Au loci and confirmed that it was not controlled by MNSs and was not X- or Y-borne.