Chuvash polycythemia
Chuvash erythrocytosis is a rare, genetic, congenital secondary polycythemia disorder characterized by increased hemoglobin, hematocrit and erythropoietin serum levels and normal oxygen affinity, which usually manifests with headache, dizziness, dyspnea and/or plethora. Patients present an increased risk of hemorrhage, thrombosis and early death.