Abstract
Down syndrome (DS) is one of the most common congenital syndromes in humans. The cause of DS is complete or partial trisomy of chromosome 21.
The disease is associated with a typical phenotypic manifestation and a higher risk of health complications, including haemato-oncological diseases. The most serious haematological complications include transient myeloproliferative disease (TMD), myelodysplastic syndrome and acute leukaemia.
TMD affects up to 10% of new-borns with DS. While spontaneous remission occurs in most cases, 20-30% of cases develop into acute leukaemia.
Acute leukaemia associated with DS is most often of myeloid origin, rarely of lymphoid origin. TMD is not defined by unambiguous morphological criteria and characterised by the transient presence of megakaryocyte lineage blasts in the peripheral blood of children with chromosome 21 trisomy.