Using our murine model of chronic IH, we demonstrated that HIF-1 plays a major role to trigger IH-induced ER stress and apoptosis, since IH-induced expression of both Grp78 and CHOP, as well as apoptosis, were prevented in HIF-1α+/− mice (Figure 7A). The gene discussed is HSPA5; the disease is isolated hemihyperplasia.