PMC6797852_01
Abnormal cytogenetic and FISH findings in Patient #1. (A) Representative karyogram of an apparent t(8;21)(q22;q22) observed in 11 of 20 metaphases analyzed, unable to show submicroscopic small deletions due to cytogenetic technic limitation. The aberration was re-written as der(8)t(8;21)(q22;q22),der(21)del(8)(q22q22)t(8;21) based on FISH findings in (B,C). Arrows indicate aberrant chromosomes. Chromosome numbers are listed on the bottom. (B) Interphase FISH study using dual color dual fusion probes demonstrating an atypical pattern with one fusion signal for RUNX1-RUNXT1, one signal (red) for the RUINX1T1 locus, and two signals (green) for the RUNX1T1 locus. (C) Metaphase FISH study using dual color dual fusion probes demonstrating a derivative chromosome 8 [der(8)] carrying a fusion signal of RUNX1T1 and RUNX1, a derivative chromosome 21 [der(21)] carrying the green colored RUNX1 signal alone consistent with a sub-microscopic deletion of the rearranged 8q22 segment encompassing the 5' RUNX1T1, a copy of a normal chromosome 8 [N(8)] and a copy of a normal chromosome 21 [N(21)].
fonc-09-01016-g0001.jpg
PMC6797852_01_fonc-09-01016-g0001.jpg
F1
FISH on interphase nuclei showed an atypical pattern with one fusion signal representing either der(8) or der(21) (indistinguishable on interphase nuclei) resulting from a typical translocation, two green signals (2G) representing either an intact or partial RUNX1 (AML1) gene at 21q22, and a single red signal (1R) representing either an intact or partial RUNX1T1 (ETO) gene at 8q22. FISH on metaphases showed a derivative chromosome 8 carrying a fusion signal of RUNX1T1 and RUNX1, a derivative chromosome 21 carrying the green colored RUNX1 (AML1) signal alone consistent with an absence of the RUNX1T1 (ETO) signal and indicative of a sub-microscopic deletion following the t(8;21) (the green signal in fact represented the 3' RUNX1 gene), a copy of a normal chromosome 8 (red), and a copy of a normal chromosome 21 (green) (Figure 1).
PMC6797852_02
Abnormal cytogenetic and FISH findings in Patient #2. (A) Representative karyogram of an apparent t(8;21)(q22;q22) observed in all of 20 metaphases analyzed, unable to show submicroscopic small deletions due to cytogenetic technic limitation. The aberration was re-written as der(8)t(8;21)(q22;q22),der(21)t(8;21)del(8)(q22q22) based on FISH findings in (B,C). Arrows indicate aberrant chromosomes. Chromosome numbers are listed on the bottom. (B) Interphase FISH study using dual color dual fusion probes demonstrating an atypical pattern with one fusion signal for RUNX1-RUNXT1, one signal (red) for the RUINX1T1 locus, and two signals (green) for the RUNX1T1 locus. (C) Metaphase FISH study using dual color dual fusion probes demonstrating a derivative chromosome 8 [der(8)] carrying a fusion signal of RUNX1T1 and RUNX1, a derivative chromosome 21 [der(21)] carrying the green colored RUNX1 signal alone consistent with a sub-microscopic deletion of the rearranged 8q22 segment encompassing the 5' RUNX1T1, a copy of a normal chromosome 8 [N(8)] and a copy of a normal chromosome 21 [N(21)]. (D) Interphase FISH study using dual color dual fusion probes demonstrating a second atypical pattern with two signals (red) for the RUINX1T1 locus, three signals (green) for the RUNX1T1 locus and no fusion signal for RUNX1-RUNXT1.
fonc-09-01016-g0002.jpg
PMC6797852_02_fonc-09-01016-g0002.jpg
F2
TP53 deletion was observed (Figure 2). The final cytogenetic diagnosis for this patient was: