Sickle cell anemia and transposition of the great vessels.

A child with homozygous sickle cell disease and transposition of the great vessels had erythrocytosis associated with markedly increased plasma erythropoietin activity. Her clinical course was complicated by neurologic manifestations but not by recurrent sickle cell vasooculsive episodes. The fetal hemoglobin level which had been greater than 25% during the first two years of life gradually decreased to less than 10%. She died at 3 years of age of congestive heart failure and severe anemia. The only sickle cell painful crisis occurred during her terminal illness. It is likely that the high levels of fetal hemorglobin decreased sickling and thus allowed erythrocytosis to develop. Fetal hemoglobin may also have prevented frequent vaso-occlusive events despite the high hematocrit level.