[Myelodysplasia in children and mitochondrial cytopathies].

Sideroblastic anemia associated with vacuolization of haemopoietic precursors can be observed in some constitutional diseases associated with mitochondrial DNA deletion. In this condition, it is the haematological expression of a multi-tissue disorder. Haemopoiesis is polyclonal, without abnormality of nuclear DNA differing from the acquired idiopathic sideroblastic anemias which arise from a clonal transformed stem cell. This model of childhood polyclonal myelodysplasia can be observed in others myelodysplasias associated with constitutional polymalformative syndromes.