CHROMOSOME PATTERNS IN 26 SOUTH-AFRICAN CHILDREN WITH ACUTE NONLYMPHOCYTIC LEUKEMIA (ANLL)

Of 46 black leukemic children 52% had acute nonlymphocytic leukemia (ANLL), whereas only 11% of 62 white leukemic children had the disease. An abnormal karyotype was found in 73% of the 26 children with ANLL and the majority of abnormal karyotypes were pseudodiploid. Balanced translocations were noted in 10 children, of whom 4 had t(8;21) associated with M2 ANLL, 2 had t(15;17) and M3 ANLL, 2 had a t(9;22), 1 child with M5 ANLL had t(10p;11q) and an infant with congenital M5 ANLL had t(8;16). Monosomy #7 was detected in 2 preleukemic children who subsequently developed M4 ANLL. Hyperdiploidy was present in only 3 cases. These patterns were compared with those of other published series, confirming the increased frequency of chromosome abnormalities in children with ANLL. The differing ratio of ANLL:ALL, some of the distinctive clinical features, and the high frequency of detectable chromosome abnormalities in black children may be reflections of a particular oncogenic agent(s) within their environmental background that could be responsible for the initiation of the leukemic process.