Proliferation of abnormal blood cell precursors in the marrow that results in decreased peripheral blood cell counts and in some instances may progress to acute leukemia

A group of neoplasms that originate in a primitive multipotential hematopoietic cell.. About half of the cases are mild to moderate anemias accompanied by mild to moderately reduced white cell and platelet counts. Often, these are not progressive but they have a heightened propensity to evolve into acute myelogenous leukemia. The other half of the cases are a type of low blast count leukemia that may be associated with severe white cell and platelet deficits. Many of the patients affected require transfusion therapy, have a propensity to infection or to bleeding, and frequently progress to more overt leukemia. These disorders can occur at any age but are most common after age 60 years.

a clonal disorder of bone marrow resulting in the production of morphologically and functionally abnormal red cells, white cells, and platelets

Defective development of any part of spinal cord.

Defective formation of the spinal cord.

Any defect in the spinal cord; occurs during fetal development.