About Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a group of diseases characterized by ineffective hematopoiesis.1 For unknown reasons, the bone marrow begins producing dysplastic myeloid stem cells. As the cells progress toward differentiation, they stall in the maturation process.1 These cells have chromosomal abnormalities, typically an addition or deletion, which they pass on to their progeny.1

The cells also produce toxins that cause extensive apoptosis of healthy cells, helping the dysplastic cell lines achieve an advantage over healthy cells in subsequent generations.1, 2 The result is very active hematopoiesis that produces many immature myeloblasts and ineffective blood cells.1

Since the blasts do not mature, the population of healthy blood cells declines, as do the functions associated with the cells.1 The consequences of these declines can be minimal in early phases of the disease or in its mildest forms.2 Late effects of severe disease are significant and often terminal and can include anemia, leukemia, thrombocytopenia, or a combination of these cytopenias.1

Diagnosing MDS involves first ruling out other causes of symptoms, such as vitamin deficiencies and infections.1 Bone marrow biopsies and analyses also are required.1 The International Prognosis Scoring System uses the variables within the World Health Organization schema to predict patient outcomes on a 0 - 2.5 point scale. In general, the more cytopenias, blasts and cytogenetic abnormalities the patient has, the worse the prognosis.2

The prevalence of MDS is narrowly focused; it primarily occurs in people age 60 or older, and especially in Caucasian men.2 The etiology of MDS is not well known. There are no proven causes, and while it typically appears de novo, it can occur secondary to radiation exposure or myelotoxic chemotherapy.1, 2

In this section you will find more information on the following MDS topics:

• Etiology
• Consequences
• Prevalence
• Diagnostic Scoring Systems
• Epigenetics and the Role of Methylation

This site also provides comprehensive information on managing and treating MDS, including current treatment options and the latest developments in MDS treatment.