When you have the rare but treatable disorder known as aplastic anemia, your marrow -- the spongy substance inside your bones -- stops making new blood cells. Sometimes it stops making just one type, but more often you become low on all three: red and white cells, and platelets.
It can develop slowly or come on suddenly. If your blood count gets low enough, it can be life-threatening.
About 12,000 Americans develop different types of myelodysplastic syndrome each year. The risks of MDS increase with age. Factors that raise your risk of these problems include:
Cancer therapy. The use of certain chemotherapy drugs for cancer plays a role in many cases of later myelodysplastic syndrome. MDS may be more likely to occur after treatment for acute lymphocytic leukemia in childhood, Hodgkin's disease, or non-Hodgkin's lymphoma.
Cancer drugs linked to myelodysplastic syndrome include:
Some inherited conditions raise people's risk of having myelodysplastic syndrome. These include:
Fanconi anemia. In this condition, the bone marrow fails to make sufficient amounts of all three types of blood cells.
Shwachman-Diamond syndrome. This keeps the bone marrow from making enough white blood cells.
Severe congenital neutropenia. This condition is marked by insufficient neutrophils, which are a type of white blood cell.
Exposure to chemicals. You may be more likely to develop myelodysplastic syndrome if you're exposed to certain industrial chemicals over a long period of time. Smoking also raises people's risk of MDS.