Identification of the novel fusion gene MLL-DIAPH2 in an AML sample with t(X;11)(q13;q23). (A) Structure of the MLL (KMT2A) and DIAPH2 genes indicating the DNA breakpoint regions in MLL intron 10 and DIAPH2 intron 4 in this patient with a t(X;11)(q13;q23). (B) Structure of the MLL-DIAPH2 fusion gene verified using PCR amplification and Sanger sequencing of leukemic DNA using primers 1 and 2 (p1 and p2) and cDNA using primers 3 and 4 (p3 and p4). Gel electrophoresis and Sanger sequencing of the PCR product from each experiment are shown delineating translocation breakpoint in DNA sequence (intron 10 of MLL and intron 4 of DIAPH2), and in cDNA (exon 10 of MLL and exon 5 of DIAPH2). (C) Protein structure of MLL, DIAPH2, and (predicted) MLL-DIAPH2 fusion. AT, adenine-thymine hook DNA-binding; BCR, breakpoint cluster region; bkpt, breakpoint; BRD, bromodomain; CXXC, cysteine-X-X-cysteine; DAD, diaphanous autoregulatory domain; FH1-3, formin homology 1-3; FYRC, phenylalanine (F)/tyrosine (Y)-rich C-terminal; GBD, rho GTPase-binding; PHD, plant homeodomain; SET, Su(var)3-9, Enhancer-of-zeste and Trithorax.