Abstract
In a patient with chronic erythroleukaemia in isochromosome 17q was identified in all bone marrow metaphases analyzed. In addition, these cells were characterized by hypodiploidy and the presence of 3 different marker chromosomes. Approximately 50% of dividing cells in the marrow were bizarre-looking polyploids. The identification by Giemsa banding of i(17q) in this case of erythroleukaemia supports the concept that there are common cytogenetic characteristics among malignant myeloproliferative disorders.