Myelodysplastic Syndrome with Ring Sideroblasts
Sideroblastic anaemias are characterized by the presence of ring sideroblasts in the bone marrow. There are two forms of sideroblastic anaemias, congenital sideroblastic anaemias (hereditary, Congenital Sideroblastic Anaemias and acquired (not inherited) sideroblastic anaemias including a well-defined subtype of myelodysplastic syndrome (MDS) who have ringed sideroblasts (RARS, RARS-T and RCMD-RS).
MDS are clonal disorders of hematopoietic stem cells characterized by peripheral cytopenia and propensity to progress to acute myeloid leukemia (AML). Refractory anemia with ringed sideroblasts (RARS) and refractory cytopenia with multilineage dysplasia and ringed sideroblasts (RCMD-RS) are two well-defined subtype of MDS phenotypically characterized by the presence of ring sideroblasts.
Iron overload is common in patients with MDS and adversely affects survival in these patients (worse overall survival and leukemia-free survival). Prolonged therapy red cell transfusion is a contributing factor to iron overload, although many patients develop an iron overload at an early stage of the disease, even before transfusion, probably due to an ineffective erythropoiesis. Therefore, an iron chelation therapy is beneficial in these patients.
Recently, it has been described that somatic mutations in the gene SF3B1 (a gene involved in RNA splicing machinery) are particularly frequent (60-80%) in patients with MDS-ARSA or RCMD-RS (Papaemmanuil E et al. NEJM 2011).
Our laboratory performs genetic diagnosis of MDS with ring sideroblasts by partial or complete Sanger sequencing of the gene SF3B1 in peripheral blood (or DNA from peripheral blood) or in blood from bone marrow aspirate (or DNA).