Application of Microarray-Based Comparative Genomic Hybridization in Prenatal and Postnatal Settings: Three Case Reports

Figure 2

Complex rearrangement is revealed by array CGH. (a) FISH studies using acro-p probe targeting the short arms of all acrocentric chromosomes (red) were used to investigate the additional satellite on the long arm of 21qs. Insert shows the G-banded 21 chromosome with additional satellite on 21q (as indicated by ∗). (b) FISH studies using probes targeting 21q22 locus (encompassing RUNX1 gene, aqua) and 21qter locus (yellow) were used to lineate the deleted chromosome 21. The del(21) lacks the yellow signal for the 21qter locus and has a diminished signal for the 21q22 locus. The 4pter and 4qter probes were used because they are in the same cocktail with the 21q22 and 21qter probes (Abbott Molecular Inc. ToTelVysion Vial no.4 probe set). (c) By using the RUNX1/RUNX1T1 (previously known as AML1/ETO) dual color dual fusion translocation probe set (Abbott Molecular Inc), the FISH studies confirmed the diminished signal for the RUNX1 locus. (d) Array CGH study detected a complex rearrangement on the long arm of chromosome 21 with 3 copy number gains and 2 copy number losses. (e) The second copy number variation (highlighted by the broken line in (d)) contains multiple annotated genes including RUNX1, as shown by the UCSC genome browser.