Experimental Factor Ontology identifier EFO_0004251 (myeloproliferative disorder) is a clonal hematopoietic stem cell disorder, characterized by proliferation in the bone marrow of one or more of the myeloid (i.e., granulocytic, erythroid, megakaryocytic, and mast cell) lineages. It is primarily a neoplasm of adults. (WHO 2008). Also known as: CMPD, CMPD, U, MPD, MPN, chronic myeloproliferative disease, chronic myeloproliferative disorder, chronic myeloproliferative neoplasm, myeloproliferative neoplasm.