There are five levels of myelodysplasia, and level 5 is generally considered to be extremely hypoproliferative and abnormal; however, there is no such thing as myelodysplasia level 5. The five levels of myelodysplasia are extremely active myelodysplasia, markedly active myelodysplasia, active myelodysplasia, hypomyelodysplasia, and extremely hypomyelodysplasia. Extremely low myelodysplasia is seen in aplastic anemia, among others, and is abnormal. In normal people, the degree of bone marrow proliferation tends to be markedly active, hyperplastic, and hypoproliferative, depending on age, e.g., markedly active bone marrow proliferation in young people, active bone marrow proliferation in middle-aged people, and hypoproliferative bone marrow proliferation in older people. Consult a hematologist for specific knowledge and disease diagnosis.