Tandem triplication of the long arm of chromosome 1, trp(1)(q21q32), in two cases with myelodysplastic syndromes

Abstract

 We report here two cases with myelodysplastic syndromes (MDS) carrying tandem triplication of the long arm of chromosome 1. The first case involved a 66-year-old man who presented with thrombocytopenia and monocytosis. Although hematopoietic dysplasia was minimal, cytogenetic analysis of the bone marrow revealed trp(1)(q21q32) in all metaphases analyzed, and the karyotype was determined as 46,XY,trp(1) (q21q32),add(3)(p25)[20]. The second case was a 58-year-old woman who initially presented with bilateral pulmonary infiltration indicative of alveolar proteinosis. Blood tests showed pancytopenia with few blasts, and the bone marrow picture fulfilled the criteria of refractory cytopenia with multilineage dysplasia. The karyotype was 46,XX,trp(1)(q21q32)[20]. Fluorescence in situ hybridization using a probe for the pre-B-cell leukemia homeobox 1 gene localized on 1q23 showed 3 fluorescence signals tandemly aligned on the trp(1) (q21q32) chromosome. Because trp(1)(q21q32) was the sole chromosomal abnormality (case 2) or was accompanied by only a single additional abnormality (case 1), trp(1)(q21q32) may be the primary cytogenetic change in a small fraction of MDS cases.