The OMIM (https://omim.org/, accessed on 24 December 2021) database categorizes VHL-induced erythrocytosis as familial erythrocytosis ECYT2, displaying features of both primary and secondary erythrocytosis, such as hypersensitivity of erythroid progenitors to circulating EPO, as well as raised blood EPO levels [187]. The gene discussed is EPO; the disease is familial polycythemia.