KLF1 differentially expressed genes. (A) Hierarchical clustering of RNA samples from ex vivo cultured primary erythroid cultures and the proband (column 6), color coded by expression level. Cluster 1 contains genes that are upregulated during normal terminal erythroid differentiation (OrthoC), but not in the proband. Cluster 2 contains genes, which are normally upregulated at the polychromatic erythroblast stage (PolyC), then down regulated in OrthoC, but not expressed in the proband. Cluster 3 contains genes that are more highly expressed in the proband than any of the stages of normal erythroid differentiation. Cluster 4 contains a list of genes that are highly expressed in normal proerythroblasts (ProE), then downregulated upon normal terminal differentiation. (B) Venn diagram of overlap of differentially expressed genes from Cluster 1 and from mouse Klf1-dependent genes as determined in reference 29 (ie, those genes with significantly less expression in fetal liver from Klf1^−/− mice vs Klf1^+/+ litter mates). (C) Overlap of differentially expressed genes from Cluster 2 with mouse Klf1 differentially expressed genes. (D) Overlap of differentially expressed genes from Cluster 3 with those genes upregulated in Klf1^−/− mouse fetal liver.