Loss of SP3 reduced the number of CD31+RUNX1+c-KIT+ IACs in the lumen, and CD31+RUNX1+c-KITlo/− HE cells in the wall of the dorsal aorta, consistent with a role for SP3 in specifying HE (Fig. 7A–C). This evidence concerns the gene SP3 and hereditary elliptocytosis.