IKZF1 Δ4-7 breakpoints. (A) Schematic representation of Δ4-7 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 3) and distal (intron 7) regions. The most frequent breakpoints occur at 50380384 and 50380388 in the proximal region and at 50431125 and 50431128 in the distal region. Primers used were D1 and D2 (supplemental Table 2); products were then directly sequenced to characterize the sequence flanking deletion breakpoints. (B) Pherograms of sequencing of IKZF1 Δ4-7 breakpoints. Regions matching the reference genomic IKZF1 sequence are shown by arrows, separated by additional nucleotides not matching the consensus sequence.