Heterogeneity of the erythropoietic defect in two cases of Aase-Smith syndrome.

Here we report two children with Aase-Smith syndrome (triphalangeal thumbs and congenital red cell plasia). In vitro growth of erythroid colonies was normal in the first patient and totally absent in the other. In both patients, treatment with glucocorticoids induced remission of anemia. Our results suggest that the different growth patterns of erythroid colonies observed in the two patients could reflect the defect of erythroid differentiation occurring at discrete maturational levels.