<prompt> Barts hydrops fetalis is lethal becauseHb Barts cannot bind oxygenThe excess a globin form insoluble precipitatesHb Barts cannot release oxygen to fetal tissuesMicrocytic red cells become trapped in the placental  <response>: In the foetus excess, gamma globin chains form tetramers 1Ib Barts with such high affinity for oxygen that they deliver almost no oxygen to tissues - RobbinsClinically this condition manifests as hydrops fetalis and fetus shows features similar to those of erythroblastosis fetalis Severe pallor, Generalized edema, Massive hepatosplenomegaly 