title: An active isodicentric x chromosome in a case of refractory anaemia with ring sideroblasts associated with marked thrombocytosis.
abstract: Refractory anaemia with ring sideroblasts and marked thrombocytosis (RARS-T) is a provisional entity in the World Health Organization (WHO) classification. It displays features characteristic of both myelodysplastic syndrome and myeloproliferative neoplasia plus ring sideroblasts ≥15% and marked thrombocytosis. Most patients with RARS-T show a normal karyotype. We report a 76-year-old woman diagnosed with RARS-T (76% of ring sideroblasts) with JAK2 (V617F) mutation and a load of 30-40%. Classical and molecular cytogenetic (FISH) studies of a bone marrow sample revealed the presence of isodicentric X chromosome [(idic(X)(q13)]. Moreover, HUMARA assay showed the idic(X)(q13) as the active X chromosome. This finding was correlated with the cytochemical finding of ring sideroblasts. To our knowledge, this is the first reported case of an active isodicentric X in a woman with RARS-T.
authors.affiliation: Department of Haematology, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain.
authors.forename: Rosario M
authors.initials: RM
authors.lastname: Morales Camacho
authors.affiliation: Department of Genetics, Reproduction and Fetal Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Sanchez
authors.affiliation: Department of Genetics, Reproduction and Fetal Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain ; Centre of Biomedical Network Research on Rare Diseases (CIBERER), 41013 Seville, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Marcos Luque
authors.affiliation: Department of Haematology, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Bernal
authors.affiliation: Department of Haematology, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain.
authors.forename: Jose F
authors.initials: JF
authors.lastname: Falantes
authors.affiliation: Department of Haematology, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Pérez-Simón