SOX17 and hereditary elliptocytosis: To define the mechanisms of SOX17 action during the specification and diversification of HE, we established SOX17-knockout and SOX17-inducible hESC lines and assessed their differentiation in a two-dimensional (2D) chemically defined feeder- and xeno-free human pluripotent stem cell (hPSC) differentiation system in which all stages of hematopoietic development are temporally, phenotypically, and functionally defined (Uenishi et al., 2014).