MPN-associated disease driver mutations include mutations in the janus kinase 2 (JAK2, chromosomal location 9p24) gene, myeloproliferative Leukemia Virus Oncogene (MPL, chromosomal location 1p 34) gene, and calreticulin (CALR, chromosomal location 19p13.2) gene. The gene discussed is CALR; the disease is myeloproliferative neoplasm.