title: Biclonal myelodysplastic syndrome involving six chromosomes and monoallelic loss of RB1 - A rare case.
abstract: BACKGROUND
  Myelodysplastic syndrome (MDS) represents a group of clonal hematological disorders characterized by progressive cytopenia, and reflects to defects in erythroid, myeloid and megakaryocytic maturation. MDS is more frequently observed in older aged patients with cytogenetic abnormalities like monosomy of chromosome(s) 5 and/or 7. In 50% of de novo MDS cases, chromosomal aberrations are found and rearrangements involving the retinoblastoma (RB1) gene in 13q14 are found.
  
  
  RESULTS
  Here, we are presenting a case report of a rare biclonal MDS with a karyotype of 45, XY,-4, der(6)t(4;6)(p15.1;p21.3), der(8)t(4;8)(q31.2;q22), t(13;16)(q21.3;p11.2)11/45, XY, der(7)t(7;13)(p22.2~22.3;q21.3),-13 9. The patient was diagnosed according to WHO classification as refractory anemia with excess of blasts (RAEB-II).Immunophenotyping was positive for CD11b, CD11c, CD10, CD13, CD15, CD16 and CD33.
  
  
  CONCLUSIONS
  We report, a novel and cytogenetically rare case of a biclonal MDS with complex chromosomal aberrations and deletion of RB1-gene in both clones. These findings are associated with a poor prognosis as the patient died 3 months after diagnosis.
authors.affiliation: Molecular Biology and Biotechnology Department, Human Genetics Division, Atomic Energy Commission, Damascus, Syria. ascientific@aec.org.sy.
authors.forename: Walid
authors.initials: W
authors.lastname: Al-Achkar
authors.forename: Abdulsamad
authors.initials: A
authors.lastname: Wafa
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Klein
authors.forename: Abdulmunim
authors.initials: A
authors.lastname: Aljapawe