RUNX1/AML1 gene lesions in MDS/AML of several FA patients. (A) Overview of the chromosomal and molecular lesions detected on the RUNX1 gene locus at 21q22 in the BM cells of 6 FA patients with MDS/AML. (Top panel) The genomic position of the RUNX1 exons and of the FISH probes. (Bottom panel) Deletions and gains are represented in green and red, respectively. In patient EGF111, 2 unbalanced translocations involved chromosome 21, the most telomeric interrupting RUNX1 as indicated; a balanced translocation detected in a sixth patient (EGF201) using the RUNX1 flanking probes is not shown. (B) A 7-bp insertion in RUNX1 was found in the EGF171 patient in addition to the large deletion shown in panel A (blast cells 70%). (C) Break-apart and duplication of the 5′ telomeric RUNX1 probe (green) in patient EGF036 with a t(1;21)(p36;q22) (objective lens, original magnification × 63). A fusion PRDM16-RUNX1 was confirmed by combinations of RUNX1 and PRDM16 probes (not shown).