Although the role of master regulator of this conversion of HE cells pertains to RUNX1, its first action is to directly drive the expression of the GFI1/GFI1B factors, and it has been shown that forced expression of both can compensate for the loss of RUNX1 in this process (Lancrin et al., 2012). The gene discussed is GFI1; the disease is hereditary elliptocytosis.