Leukemia is a type of cancer that affects the white blood cells. In this handout, you will learn about leukemia and how it affects people with Down syndrome. Source: Mass General Down Syndrome Program Tags:acute lymphoid leukemiaacute megakaryoblastic leukemiaacute myeloid leukemiaALLAMKLAMLblastsbloodbone marrowCancerleukemiaMDSmyelodysplastic syndromeTMDtransient myeloproliferative disorderwhite blood cells