Myelodysplastic syndrome (MDS) is a condition that affects the bone marrow and the blood cells it produces.
Your bone marrow makes different types of blood cells:
Red blood cells, which carry oxygen in your blood.
White blood cells of different types, which are important elements of your immune system.
Platelets, which help your blood to clot.
Your bone marrow needs to produce the proper number of these cells. And the cells need to have the right shape and function.