Schematic representation and restriction enzyme map of the chromosome 3 germ-line configuration (BCL6 gene locus) and the chromosome 7 derivative (der 7).

The 3q27 regions are shown by lines, and the 7p12 region by hatched bars. The breakpoint is indicated with a vertical arrow, and the presence of the Ikaros coding-exon 1 with a dashed vertical arrow. Exons I to III of the BCL6 gene are boxed. A BCL6 major translocation cluster (MTC) probe was used to screen a genomic DNA library constructed from patient 2.