<unk>  is a rare, noncancerous disorder in which the blood marrow is unable to adequately produce blood cells required for survival. It is estimated that the incidence of<unk>  is 0.7–4.1 cases per million people worldwide, with the prevalence between men and women being approximately equal. The incidence rate of<unk>  in Asia is 2–3 times higher than it is in the West; the incidence in the United States is 300–900 cases per year. The disease most commonly affects adults aged 15–25 and over the age of 60, but it can be observed in all age groups. The disease is usually acquired during life and not inherited. Acquired cases are often linked to environmental exposures such as chemicals, drugs, and infectious agents that damage the bone marrow and compromise its ability to generate new blood cells. However, in many instances the underlying cause for the disease is not found. This is referred to as idiopathic<unk>  and accounts for 75% of cases. This compromises the effectiveness of treatment since treatment of the disease is often aimed at the underlying cause. Those with a higher risk for<unk>  include individuals who are exposed to high-dose radiation or toxic chemicals, take certain prescription drugs, have pre-existing autoimmune disorders or blood diseases, or are pregnant. No screening test currently exists for early detection of<unk> .
Aplastic anemia
Acute lymphoblastic leukemia
Refractory anemia with excess of blasts
Polycythemia vera
Myelodysplastic syndrome
Myomatous erythrocytosis syndrome
Essential thrombocythemia
Refractory cytopenia of childhood