Acute myelogenous leukemia in a child with primary involvement of chromosomes 11 and X

The chromosomes of a case of acute myelogenous leukemia in an infant of 7 months were analyzed by means of high resolution banding achieved without mitotic synchronization. The analyses were based on 2 cell samples taken, (1) at diagnosis before treatment, and (2) 3 months later during partial remission, before the onset of the terminal phase. All cells of both samples contained 2 deviating chromosomes resulting from rearrangements of X at q22 and of 11 at p13, p15 and q23. Twenty-seven per cent of the cells of the first sample and 51 % of the second sample in addition had an inverted (mirror) duplication of the “variable” region of the long arm of chromosome 1 (1q12). At the second fixation this cell clone had undergone further evolution leading to one clone with trisomy for the distal half of the short arm of chromosome 6 (6p21.2-pter) and another clone with rep t(7;12) (q13;q15). The involvement of chromosome 11 in malignant blood disorders is discussed with special emphasis on acute nonlymphocytic leukemia of the childhood.