Familial erythrocytosis arising from a gain-of-function mutation in the HIF2A gene of the oxygen sensing pathway.

A mutation of HIF-2 alpha has been detected in three generations of a family with erythrocytosis and the mutation co-segregated with the erythrocytosis phenotype. Functional studies revealed that Gly537Trp mutation would significantly impair the function of HIF-2 alpha thus leading to increased synthesis of Epo. In addition to VHL and PHD2 a further member of the oxygen sensing pathway, namely HIF-2 alpha,can be a cause of erythrocytosis. Furthermore, HIF-2 alpha plays an important role in the regulation of Epo production. Continued study of idiopathic cases of erythrocytosis with raised serum Epo will reveal whether HIF-2 alpha will be a major cause of erythrocytosis on par with VHL.