Bone marrow failure encompasses a number of diseases. This website is focused on three related bone marrow failure diseases: aplastic anemia (AA), myelodysplastic syndromes (MDS), and paroxysmal nocturnal hemoglobinuria (PNH). MDS itself is a family of diseases.
I collected some facts about AA, MDS, and PNH for you:
Aplastic anemia is acquired 80% of the time. Although it is considered an autoimmune condition, the original cause or trigger is usually unknown. Possible causes include certain chemicals (especially benzene), hepatitis and other viruses, radiation, and certain drugs. Even pregnancy has been associated with aplastic anemia.
The 20% of AA patients for whom AA is congenital (inherited) often have another diagnosis, such as Fanconi anemia, with AA not the primary diagnosis.
About two thirds of myelodysplastic syndromes (MDS) cases are idiopathic (original cause unknown). Benzene, other chemicals, and viruses may be causes, but specific exposures are usually hard to pinpoint. When a cause for MDS is known, it's often because MDS is secondary, a result of previous chemotherapy or radiation.
Paroxysmal nocturnal hemoglobinuria (PNH) is a specific genetic defect that is acquired, not inherited. It's unknown whether there is a genetic predisposition for PNH.
AA and PNH overlap; many patients have both. About 20% of AA patients also have PNH at time of first diagnosis, and immunosuppressive therapy for AA can result in PNH. Identifying risk factors for PNH, other than prior AA, is a subject of research.
See also the information and links on our
Bone Marrow Failure Diseases page.