IKZF1 Δ2-7 breakpoints. (A) Schematic representation of Δ2-7 deletion with arrows indicating the region in which the breakpoints occur. In the graphs are shown the chromosome positions of breakpoints in the proximal (intron 1) and distal (intron 7) regions. The most frequent breakpoints occur at 50317927 and 50317933 in the proximal region and at 50431128 in the distal region. Primers used were C3/C4 and C5 (supplemental Table 2); products were then directly sequenced to characterize the sequence flanking deletion breakpoints. (B) Pherograms of sequencing of IKZF1 Δ2-7 breakpoints. Regions matching the reference genomic IKZF1 sequence are shown by arrows, separated by additional nucleotides not matching the consensus sequence.