It has become increasingly clear that HE represents a distinct subset of RUNX1-expressing CD73– vascular endothelium capable of undergoing endothelial-to-hematopoietic transition (EHT) (Choi et al., 2012, Ditadi et al., 2015, Jaffredo et al., 2010, North et al., 1999, Slukvin, 2016) and that hematopoietic specification occurs at the HE stage (Elcheva et al., 2014, Guibentif et al., 2017). This evidence concerns the gene RUNX1 and hereditary elliptocytosis.