Myelodysplastic Syndrome Facts

Myelodysplastic syndromes, or MDS, refers to a group of blood disorders that affect approximately 13,000 people in the United States each year, according to the American Cancer Society. In about one-third of cases it develops into leukemia, but is a life-threatening condition on its own.

What are myelodysplastic syndromes?

Myelodysplastic syndromes is an umbrella term describing several blood disorders that begin in the bone marrow. People with MDS are unable to produce the proper amount of mature, healthy blood cells in their marrow.

Parts of the body involved in MDS include:

  • Bone marrow, spongy blood-producing tissue inside the bones, where all of the blood in the body is produced
  • White blood cells, produced in the bone marrow and a part of the immune system; a type of cell that plays an important role in fighting infection
  • Red blood cells, produced in the bone marrow, that carry oxygen throughout the body
  • Platelets, produced in bone marrow, that stop excessive bleeding by forming blood clots

In patients diagnosed with myelodsyplastic syndromes, blood cells do not mature, and these abnormal cells are either destroyed or take up space in the marrow cavity that would typically be occupied by normal cells. This lack of healthy blood cell development is what leads to symptoms associated with MDS.

Myelodysplastic syndromes symptoms

Usually there are no early warning signs of myelodysplastic syndromes. In some cases, a routine blood test for some other reason or condition will reveal problems associated with MDS. Some of the most common symptoms of MDS include:

  • Feeling weak, tired
  • Experiencing shortness of breath
  • Pale skin
  • Bruising, bleeding that happens easier than normal
  • Flat skin spots related to bleeding called petechiae

Symptoms of other medical conditions may mirror these. If you are treated for those conditions, or if your symptoms last for several weeks despite medical treatment, you may need further consultation to rule out MDS.

What increases your risk of myelodysplasia?

Things that put you at higher risk for getting MDS are called risk factors. Doctors do not know what causes most cases of myelodysplasia, and there is very little that can be done to avoid being diagnosed. Risk factors for MDS include:

  • Being treated for cancer in the past with chemotherapy; risk can increase if patient also received radiation
  • Myelodysplasia sometimes runs in families.
  • Inherited syndromes such as Fanconi anemia, Diamond Blackfan anemia, Shwachman-Diamond syndrome, familial platelet disorder, and severe congenital neutropenia can increase risk of MDS.
  • Exposure to chemicals in pesticides, fertilizers and solvents such as benzene
  • As with other types of cancer, smoking may increase risk of MDS.
  • Exposure to heavy metals like mercury or lead increases risk.
  • Age and sex are risk factors; risk increases for men and as a person ages.

Types of myelodysplastic syndromes

There are several types of myelosdysplasia — all related, yet appearing and acting differently in the body. While MDS are rare diseases overall, some types are more commonly diagnosed including:

  • Refractory cytopenia with multilineage dysplasia: A common type of myelodysplasia, RCMD involves low levels of two types of blood cells — white, red or platelets — and in 10 percent of cases will evolve to leukemia.
  • Refractory cytopenia with unilineage dysplasia: When there are unusually low levels of one type of blood cell — red, white or platelets — and normal levels of the other two the patient is said to have RCUD.
  • Refractory anemia with ring sideroblasts: When there are low levels of red blood cells and normal levels of white cells and platelets, the patient has RARS.
  • Refractory anemia with excess blasts: Divided into RAEB-1 and RAEB-2, this type of myelodysplasia involves low levels at least one blood cell type, and too many abnormal, immature blood cells called blasts in the marrow. Both types of refractory anemia with excess blasts can progress to acute myeloid leukemia, although RAEB-2 is more likely to.
  • Refractory anemia: There are too few red blood cells in the blood and the patient has anemia. The number of white blood cells and platelets is normal.
  • Unclassifiable myelodysplastic syndrome: A type of myelodysplastic syndrome that is unclassifiable, and in which the number of immature cells (blasts) is normal
  • Myelodysplastic syndrome associated with an isolated del(5q) chromosome abnormality: This type of myelodysplasia involves lower than normal levels of red blood cells, leading to anemia and an abnormal change to a chromosome in bone marrow cells.