EPAS1 and polycythemia: Not only do some canonical Type 2c VHL mutations also cause hemangiomas, a phenotype strongly linked with HIF2α signaling in Type 2a VHL disease, some VHL disease patients concurrently develop polycythemia, pheochromocytoma, and somatostatinoma, which matches the phenotypic profile of Class 1a HIF2-driven disease (Karasawa et al., 2001).