Characterization of inv dup(3q) by array CGH and FISH. A. Chromosome 3 array CGH plot. The X axis represents distal p arm to distal q arm (left to right), with the centromere designated by the vertical dotted line. The blue line is a plot of the results from an experiment of Cy5 labeled reference/Cy3 labeled patient, while the pink line is from a dye-reversal experiment (Cy5 patient/Cy3 reference). Slight separation of the plots from q22.3 to qter indicates low-level gain of this region due to marker mosaicism. B. Marker chromosome (arrow) and normal chromosome 3 homologues (arrowheads) from the same metaphase cell that was initially G-banded (left panel), then destained for FISH analyses (middle and right panels). The middle panel shows results of FISH using BAC RP11-976K13 from 3q25.32 (orange signal) and a chromosome 3 alpha satellite probe (green). Alpha satellite signal is present on the two normal homologues of chromosome 3, but absent from the inv dup(3q). The inv dup(3q) shows two sets of signals from BAC RP11-976K13. The right panel shows results of rehybridization using a subtelomeric probe mixture for chromosome 3 (red signal – 3q subtelomeric probe; green signal – 3p subtelomeric probe). Note the 3q subtelomeric signals at both ends of the inv dup(3q). C. Whole chromosome 3 paint probe, confirming that the marker consists entirely of chromosome 3 material (arrow). D. G-banded image of the inv dup(3q), with the corresponding ideogram to the right.