Myelodysplastic syndromes (MDSs) are clonal hematopoietic disorders characterized by peripheral cytopenia, ineffective hematopoiesis, and an increased risk of progression to acute myeloid leukemia (AML). Although sporadic MDS is primarily a disease of the elderly with an incidence of more than 36 per 100 000 in patients age 80 years or older,1 MDS in children (ie, patients age 18 years or younger) is a rare disease with an annual incidence of 1 to 4 cases per million