*Please note: This slide show represents a visual interpretation and is not intended to provide, nor substitute as, medical and/or clinical advice.

MDS, or myelodysplasticsyndromes, are a group of blood cancers that develop from stem cells in the bone marrow. People with MDS do not produce enough healthy blood cells. It is most common in people over 65, but younger people sometimes get it.

There are several different types of MDS. Some types are more likely to develop into leukemia than others. Your MDS might have a high, medium or low risk of turning into leukemia.

Blood cells come from the tissue inside your bones called bone marrow.

Healthy marrow includes many immature blood cells called stem cells. These develop into 3 major kinds of mature blood cells:

• Red blood cells, or erythrocytes, which carry oxygen around the body,
• White blood cells, or leukocytes, which help fight infection, and
• Platelets, or thrombocytes, which help stop bleeding after injury.

In MDS, some stem cells have genetic damage.

As these abnormal stem cells grow at the expense of normal stem cells, the production of normal, mature blood cells goes down. Doctors may say you have “low blood counts”.

Another way MDS can reduce your number of healthy, mature blood cells is through a buildup of immature stem cells – called blasts – in the bone marrow or blood. Too many blasts means fewer healthy, mature blood cells. This is another cause of low blood counts.

Cytopenia is the medical term for low blood counts. There are different types of cytopenia, depending on which cells are low.

This slide show is about having too few red blood cells, called anemia. Having too few white blood cells is neutropenia and having too few platelets is thrombocytopenia.

About 30 percent of people with MDS develop a life-threatening blood cancer called acute myeloid leukemia, or AML. The risk of AML depends on the type of MDS you have and other factors. We will learn more about your risk later in this slide show.

Up to 80 percent of people with MDS have anemia (low red blood cell production) at some time during the disease.

Doctors can identify anemia based on any of 3 values in your complete blood count, or CBC. These are your red blood cell count, hemoglobin, and hematocrit. They will usually pick 1 of these to track over time.

Symptoms of MDS-related anemia include fatigue, difficulty catching your breath, and heart palpitations (the feeling that your heart is fluttering, pounding fast, or skipping beats).

You might also feel tired, lightheaded, or short of breath after climbing stairs or doing other activities that take some effort.

Anemia can happen with conditions other than MDS. These include vitamin deficiency, bleeding disorders, severe kidney disease and cancer.

Infections and immune system diseases may also cause anemia. You will need tests to determine if you might have one of these other conditions.

Doctors learn if you have MDS, and determine what type it is, by doing blood tests, taking a sample of bone marrow in a procedure called bone marrow aspiration and biopsy, and often by genetic testing.

The pathologist who looks at your bone marrow biopsy will classify your MDS as a specific type. Currently, only 2 of these types have unique treatment options, but this might change as doctors discover more.

Your doctor will calculate a risk score based on which blood counts are low, your number of blasts, and any gene changes they see. These gene changes are usually acquired, not inherited, so they do not tend to “run in the family.”

If you have several family members with MDS or leukemia, you should have a special evaluation for an inherited condition.

MDS with multilineage dysplasia is the most common type of MDS. One or more blood cell types are low in this type of MDS, and 2 or 3 types look abnormal in the bone marrow, where they are made. If red blood cells are affected, you have anemia.

MDS with single lineage dysplasia involves having 1 or 2 types of low blood cells, but only 1 that looks abnormal in the bone marrow.

These types are less likely to develop into AML than some other MDS types.

Ring sideroblasts are groups of ring-shaped iron granules that form inside red blood cells in this type of MDS. One or more types of cells are also abnormally shaped. This type of MDS was previously called refractory anemia with ring sideroblasts. Anemia is more common in this type of MDS, and it rarely develops into AML.

MDS with isolated del(5q) is a type of MDS where there are too few of 1 or 2 different types of blood cells. This often includes red blood cells. At least 1 cell type is abnormal. The bone marrow cells have also suffered a specific type of DNA damage (the loss of one part of chromosome 5). This type of MDS does not usually develop into acute myeloid leukemia, or AML.

Immature blood cells called blasts can build up in the bone marrow or enter the bloodstream. These leukemia-like cells are part of a specific type of MDS, called MDS with excess blasts.

You also have too few of at least 1 type of blood cell. If this includes red cells, you have anemia.

Previously, this type of MDS was called refractory anemia with excess blasts. About 25 percent of MDS is this type. It is the most likely to become AML.

Unclassifiable MDS is a term used to describe some rare types of MDS that don’t quite fit other types. Doctors are not yet sure of the outlook for people with this MDS type.

Doctors give each person a risk score to show how severe their MDS is.

You now know that some types of MDS have a low or very low risk of developing AML. You might not need treatment, or you might need to take medicine to improve your blood counts and avoid getting blood transfusions.

Other MDS types have an intermediate, high, or very high chance of causing life-threatening complications or turning into AML. You will likely need treatment to lower this risk, possibly right away.

MDS is very different from person to person, so learning your type and risk group is important.

The more you know, the better decisions you can make about available treatment options.