Several instances of this doubly heterozygous state have been reported. Two families had Hb GPhiladelphiaand Hb C,3., 4., 5., 6.one had Hb GBristol and Hb C,7 one had Hb Hopkins-2 and Hb S,8,9and another had Hb DWashington and Hb C.10In addition, normal Hb A and a hybrid ...