The unbalanced 1;7 translocation in de novo myelodysplastic syndrome and its clinical implication.

In our chromosome study of 97 patients with myelodysplastic syndrome (MDS), six showed an unbalanced translocation between chromosomes 1 and 7 [-7, +der(1)t(1;7)(p11;p11)]. All of them had morphologic myelodysplasia in trilineage of bone marrow cells, and cytopenia was the major finding in the peripheral blood. All six patients had symptoms of infection at the time of diagnosis, and five showed immunologic abnormalities (polyclonal hypergammaglobulinemia in four and increased marrow plasma cells in three). None of the patients survived more than 11 months after the diagnosis; the median survival time was 4 months. Both of the two patients whose karyotypes were reexamined in the course of their disease showed karyotypic evolution accompanying the coincidental leukemic transformation. Six patients with MDS who had the same chromosome abnormality [t(1;7)] are described and their characteristic clinical features are presented.