JAK2 (Janus kinase 2) is a gene that provides instructions for making a protein involved in the regulation of cell growth and division. JAK2 exon 12 mutations are genetic alterations that occur within exon 12 of the JAK2 gene, resulting in the activation of the JAK2 protein that leads to uncontrolled cell growth and the development. These mutations are typically somatic, meaning they occur in non-germline cells and are not inherited from parents.

Mutations in the JAK2 gene, including those in exon 12, are associated with various blood disorders, most notably myeloproliferative neoplasms (MPNs). MPNs are a group of blood cancers characterized by the overproduction of blood cells in the bone marrow. One of the common MPNs associated with JAK2 mutations is polycythemia vera (PV), a disorder in which there is an excessive production of red blood cells.

Early detection and targeted treatment are essential for managing MPNs effectively. Understanding the presence of JAK2 exon 12 mutations is important for confirming the diagnosis of MPNs, guiding treatment decisions, and assessing the prognosis of the patient. Therapies targeting the JAK2 pathway, including JAK2 inhibitors, have been developed and used to manage MPNs by specifically inhibiting the activity of the mutated JAK2 protein.