[Refractory sideroblastic anemia, three cases with the same extra marker chromosome (47, Mar +) (author's transl)].

Three very similar cases of sideroblastic idiopathic anemia were respectively observed for 105, 57 and 69 months. The cytogenetic blood study was normal. But the medullary genetic findings showed marker extra-chromosome, having the same aspect in each metaphase = 47 Mar +. It was respectively found in 13 mitoses/32, 2/45 and 1/30. The study of chromosome showed that it was not a normal cytogenetic C-chromosome at all, even it seemed to be a C - X type chromosome at first. The long arms had about the same size as the one of the C- type. But the short arms were really shorter. The study on R- bands showed a chromosomic marking unkown so far. The cytogenetic abnormalities described during the sideroblastic idiopathic anemias, the rare sideroblastic idiopathic anemias where were found a C- type chromosome really identified, then the well-defined myeloproliferative disorders having an extra- C chromosome, have been looked over again through the litterature. In each of our three studies we can think that these myelodysplasia are real mysloproliferative disorders because of the same marker extra-chromosome, but even after nine months we did'nt observe any chromosomal sign of blastic transformation.