Myeloproliferative neoplasms (MPNs) are a group of blood disorders characterized by the overproduction of blood cells in the bone marrow. This can lead to an increase in red blood cells, white blood cells, or platelets, which may cause various health issues. Common types of MPNs include polycythemia vera, essential thrombocythemia, and primary myelofibrosis. These conditions are often caused by mutations in specific genes, such as the JAK2 gene. Symptoms can vary but may include fatigue, headaches, and an increased risk of blood clots. Diagnosis typically involves blood tests and bone marrow examinations to assess cell production and identify any abnormalities.