Hypo- and hypertetraploidy in a case of erythroleukemia analyzed by fluorochrome banding techniques.

Chromosome studies of a case of erythroleukemia in a 57-year-old female patient were made from bone marrow aspirates using the fluorescent primary stain/counterstain methodology. The chromosome number ranged from 42 to 110. There was a high proportion of hypotetraploid cells and a few hypertetraploid and hypooctaploid ones. Structurally normal chromosomes varied in number from cell to cell, ranging from one to seven in the polyploid cells. A number of marker chromosomes were observed, some of which occurred repeatedly in two copies per hypotetraploid cell. The chromosomes involved in aberrations were tentatively identified as #3, #5, #7, #12, #13, #15, #16, #18, #19, and #21. In the abnormal chromosome #16, which was missing a normal short arm, a new kind of heterochromatin was demonstrated by sequential staining with DA-DAPI and DAPI-AMD, suggesting de novo amplification of an A-T-rich satellite DNA sequence.