title: Clonal monosomy of chromosome 21 in a case of  myelodysplastic syndrome.
abstract: This study reports on a cytogenetic finding in a bone  marrow examination of a 47-year-old male patient treated in the Hematology and  Blood Transfusion Service of the Hospital de Base in São José do Rio Preto, São  Paulo State, Brazil. The only alteration found at diagnosis of myelodysplastic  syndrome (MDS) subtype refractory anemia with excess blasts (RAEB-2) was clonal  monosomy of chromosome 21. The patient evolved to acute myeloid leukemia type  M2 and died nine months after diagnosis. Clonal monosomy of chromosome 21, as  the only cytogenetic abnormality in MDS, has only been reported three times  previously. This uncommon cytogenetic abnormality in MDS has been associated  with a poor clinical course, although more data will be needed to determine if  this prognosis is invariable.
authors.affiliation: Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual de São Paulo Julio de Mesquita Filho, São José do Rio Preto, SP, Brasil.
authors.forename: P C
authors.initials: PC
authors.lastname: Freitas
authors.forename: A B
authors.initials: AB
authors.lastname: Carvalho-Salles
authors.forename: C F
authors.initials: CF
authors.lastname: Mendiburu
authors.forename: O
authors.initials: O
authors.lastname: Ricci
authors.forename: A C
authors.initials: AC
authors.lastname: Fett-Conte
mesh_terms: D000754:Anemia, Refractory, with Excess of Blasts / Q000175:diagnosis / Q000235:genetics*; D002891:Chromosomes, Human, Pair 21 / Q000378:metabolism; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009006:Monosomy