blood disorders
Myelofibrosis
Introduction
Myelofibrosis is a disorder in which fibrous tissue in the bone marrow replaces the blood-producing cells, resulting in abnormally shaped red blood cells, anemia, and an enlarged spleen. Myelofibrosis may occur on its own because of certain gene mutations, or it may occur as a result of other blood disorders. People may feel tired and weak, have infections, and bleed easily. Blood tests and a bone marrow biopsy are done for diagnosis. Medications and other treatments lessen the severity of anemia, increase red blood cell production, and fight infections. Sometimes stem cell transplantation is used. (See also Overview of Myeloproliferative Neoplasms .) In normal bone marrow, cells called fibroblasts produce the fibrous (connective) tissue that supports the blood-producing cells. In myelofibrosis, the fibroblasts make too much fibrous tissue, which crowds out the blood-producing cells. When this occurs, some blood-producing cells migrate from the bone marrow to the spleen and liver. Overall, Formation of Blood Cells decreases, and In addition, many of the red blood cells that are produced are immature or misshapen. Variable numbers of immature White Blood Cells and Myelofibrosis is uncommon. It may Develop on its own (called primary myelofibrosis) Accompany another disorder (called secondary myelofibrosis) Primary myelofibrosisis myelofibrosis that develops on its own, due to certain genetic mutations. It occurs most often between age 50 and 70 years, mostly in males. About half of people who have primary myelofibrosis have a mutation in the Janus kinase 2 (JAK2) gene. This gene controls certain enzymes that are involved in cell growth and the immune response. Other people have a mutation in the gene called calreticulin (CALR), which is involved in making proteins that are needed for proper cell function, or in the thrombopoietin receptor gene (MPL), which is involved in cell growth. occurs as a result of other disorders, particularly other blood disorders such as Chronic Myeloid Leukemia (CML) , 