C-group chromosome abnormalities in bone marrow cells of three children with dyshematopoiesis of unknown origin.

Clinical and cytogenetic findings in three children with dyshaematopoiesis and bone marrow aneuploidy are described. Monosomy 7 was found in immature cells of one 10-year-old boy with myelofibrosis following a 3 years evolution of severe thrombocytopenia and anaemia. Trisomy 8 was found in 80% of the bone marrow metaphases of a 5 1/2-year-old girl with aplastic anaemia and Australia antigen positivity. During a 3 year observation period the number of cells with trisomy 8 regressed and eventually disappeared. Improvement of her clinical condition is present but still limited. Trisomy 8 was also found in all bone marrow cells of an 8-year-old girl with an undefined myeloproliferative disorder. Her disease was apparently related to collagen-vascular disorders like periarteritis or other necrotizing angiitis and presented with periods of exacerbation and periods of chronic evolution. Periods of exacerbation were accompanied by excessive myeloid proliferation. Repeated bone marrow cytogenetic analysis during the acute and chronic phases showed trisomy 8 in all the metaphases analysed. During the last episode of acute illness, further clonal evolution was observed, characterized by a translocation (8;17).