Thrombopoiesis and Structural Rearrangements of the Long Arm of Chromosome 3. Review arid Analysis of Data on 64...

During the least 10 years a growing number of case reports arid small patient series have demonstrated an association between certain structural changes of the q arm of chromosom'e no. 3 (insertion, inversion, translocation (3; 3) or translocation with other chromosomes) and signs of increased platelet production and morphologic megakaryocyte abnormalitieis. Analysis of published data on 64 such patients now demonstrate that rearrangements between the two chromosomes 3 are associated with significantly higher platelet counts and higher frequencies of megakaryocytes in the marrow than are translocations between no. 3 and other chromosomes. Further, the megakaryocyte hyperplasia is due primarily to abnormally small megakaryocytes, often with hypolobulated nuclei. These quantitative,and qualitative changes of thrombopoiesis are associated with coincident breaks in 3q21 an8d 3q26 and juxtaposition of these bands so that the band sequence 3q21::q26 is formed. Apparently, this band sequence specifically stimulates and changes thrombopoiesis.