But while in vitro studies failed to associate pheochromocytoma pathogenesis with HIF stabilization in the context of VHL disease, clinically observed EPAS1 (encodes HIF2α) and EGLN1 (encodes PHD2) mutations that result in HIF2α stabilization are now known to cause disease phenotypes that partially overlap with the VHL disease spectrum. This evidence concerns the gene EGLN1 and von Hippel-Lindau disease.