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510 Part VI: The Erythrocyte Chapter 34: Clinical Manifestations and Classification of Erythrocyte Disorders 511

loss-of-function PHD2 variants (encoded by EGLN1 gene) have normal
O transport (Cardiac output x Hct) EPO levels.
2
Because of the rarity of HIF2a and PHD2 mutations, their non-
erythroid phenotype is not well defined; however, some HIF2a muta-
Severe tions, possibly associated with genetic mosaicism, are associated with
hypervolemia
4 congenital polycythemia and later development of pheochromocytoma/
paraganglioma and somatistatinoma tumors. In these instances, in most
patients, the HIF2a mutation is present in the tumors, which frequently
Oxygen transport 1 3 hypervolemia recur, but not in leukocytes. 44,45
2

Moderate
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2
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2
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2
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