Nonmosaic somatic HIF2A mutations associated with late onset polycythemia-paraganglioma syndrome: Newly recognized subclass of polycythemia-paraganglioma syndrome.

These findings suggest that newer techniques need to be developed to detect somatic mosaicism in patients with this syndrome. Absence of HIF2A mosaicism in patients with somatic HIF2A mutations supports association with late onset of the disease, milder clinical phenotype, and an improved prognosis compared with patients who have HIF2A mosaicism.