title: Splicing factor SF3B1 mutations and ring sideroblasts in myelodysplastic syndromes: a Brazilian cohort screening study.
abstract: BACKGROUND
  Myelodysplastic syndromes (MDS) comprise a group of malignant clonal hematologic disorders characterized by ineffective hematopoiesis and propensity for progression to acute myeloid leukemia. Acquired mutations in the gene encoding RNA splicing factor 3B subunit 1 (SF3B1) are highly associated with the MDS subtypes presenting ring sideroblasts, and represent a specific nosological entity. The effects of these mutations on clinical outcomes are diverse and contrasting.
  
  
  METHODS
  A cohort of 91 Brazilian MDS patients, including patients with ring sideroblasts in the bone marrow, were screened for mutations in the SF3B1 hotspots (exons 12-15) by direct Sanger sequencing.
  
  
  RESULTS
  SF3B1 heterozygous mutations were identified in six patients (7%), all of them with ring sideroblasts, thus confirming the association between SF3B1 mutations and myelodysplastic syndrome subtypes bearing this morphologic feature (frequency of 6/13, p-value<0.0001).
  
  
  CONCLUSIONS
  This is the first screening of SF3B1 mutations in a cohort of Brazilian myelodysplastic syndrome patients. Our findings confirm that mutations in this splicing gene correlate with bone marrow ringed sideroblasts.
authors.affiliation: Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Flávia Sacilotto
authors.initials: FS
authors.lastname: Donaires
authors.affiliation: Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Felipe
authors.initials: F
authors.lastname: Martelli
authors.affiliation: Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Raquel de Melo
authors.initials: RM
authors.lastname: Alves-Paiva
authors.affiliation: Universidade Federal do Ceará (UFC), Fortaleza, CE, Brazil.
authors.forename: Silvia Maria Meira
authors.initials: SM
authors.lastname: Magalhães
authors.affiliation: Universidade Federal do Ceará (UFC), Fortaleza, CE, Brazil.
authors.forename: Ronald Feitosa
authors.initials: RF
authors.lastname: Pinheiro
authors.affiliation: Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil. Electronic address: rtcalado@fmrp.usp.br.
authors.forename: Rodrigo Tocantins
authors.initials: RT
authors.lastname: Calado
keywords: Myelodysplastic syndromes; Ring sideroblasts; SF3B1