Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Myelodysplastic syndromes ?
    ### Response:
    Myelodysplastic syndromes (MDS) are a rare group of blood disorders characterized by abnormal development of blood cells within the bone marrow. Individuals with MDS have abnormally low blood cell levels (low blood counts). Signs and symptoms associated with MDS include dizziness, fatigue, weakness, shortness of breath, bruising and bleeding, frequent infections, and headaches.
    