_:vb50955764 . _:vb50955764 . _:vb50955764 "url:https://www.nhlbi.nih.gov/health-topics/polycythemia-vera"^^ . _:vb50955764 . _:vb50955764 . _:vb50955764 . _:vb50955764 "url:https://rarediseases.info.nih.gov/diseases/7422/polycythemia-vera"^^ . _:vb50955764 "A bone marrow disease characterized by an increased number of red blood cells in the bloodstream resulting in thicker blood and reduced blood flow."^^ .