To determine the role of Hhex in regulating Vegf signaling during HE differentiation, we treated day-one HE cultures with 1) CBO-P11 to decrease Vegf signaling in Hhex-/- cells, and 2) exogenous VEGFA to increase Vegf signaling in Hhex+/+ cells (Fig 5A). The gene discussed is HHEX; the disease is hereditary elliptocytosis.