Myelodysplastic syndrome, formerly known as preleukemia, is a group of blood disorders caused by immature and defective blood cells. These unhealthy blood cells die in the bone marrow and ultimately outgrow the number of healthy blood cells. With unhealthy blood cells, patients with myelodysplastic syndrome are susceptible to infection, anemia or easy bleeding.
Types of Myelodysplastic Syndrome
There are different types of myelodysplastic syndrome based on the type of blood cells (red cells, white cells and platelets). Types of myelodysplastic syndrome include:
- Refractory anemia – too few red blood cells and the patient is anemic
- Refractory anemia with ring sideroblasts – insufficient red blood cells containing excess amounts of iron (ring sideroblasts)
- Refractory anemia with excess blasts – low number of abnormal red blood cells, white blood cells or platelets with immature blood cells (blasts). This myelodysplastic syndrome could lead to acute myeloid leukemia
- Refractory cytopenia with multilineage dysplasia – two of the three types of blood cells are abnormal with less than one percent of the blood cells that are immature
- Unclassified myelodysplastic syndrome - reduction in one of the three types of mature blood cells
- Myelodysplastic syndrome associated with isolated del (5q) chromosome – Not enough red blood cells in the blood with a specific defect in the DNA
Risk Factors for Myelodysplastic Syndrome
There are certain risk factors associated with myelodysplastic syndrome. The risk factors include the following:
- Male, age 60 or older
- Prior treatment of chemotherapy or radiation therapy
- Exposure to certain chemicals, like pesticides, fertilizers, tobacco smoke and benzene
- Exposure to mercury or lead
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