Irreversible chorea as the initial presentation of polycythemia rubra vera in an elderly woman

Janus Kinase 2 (JAK2) protein controls the signal transduction of the erythropoietin, thrombopoetin, and related receptors that control erythrocyte and megakaryocyte expansion. A somatic mutation of JAK2-V617F in the exon 14 of the JAK2 gene (9p24) is the most common cause of myeloproliferative