Schematic representation of the rearranged chromosomes 5 and 11 in patients no. 1, 2 (A), and 3 (B). In each case, the normal chromosome homologue is shown on the left. The proximal breakpoints of the deletions are based on banding studies. In (A), the distal 5q deletion breakpoint and the 5q translocation breakpoint could not be distinguished: both were distal to NPM1. TheNPM1 gene sequence was deleted from the der(5), with theFLT4 sequence present, although translocated to the der(11). The 5q translocation breakpoint in (B) was also between theNPM1 and FLT4 genes. However, in this case, the 5q deletion was proximal to the translocation, with a distal breakpoint between the 5q31 probe and the ADRB2 gene (5q31.3). The 11p translocation breakpoint was the same in all 3 cases, between theHRC and RDPX1 genes on 11p15.5.