M-FISH of the aberrant chromosomes of patient 1 A), patient 2 B). A partial M-FISH metaphase shows the four derivative chromosomes for both patients. C) The separate fluorochrome signal intensities for the aberrant chromosome in contrast to the normal chromosomes in patient 1 show a slight increase of the blue colour DEAC on the interface between chromosome 18 (combined red, yellow and green signal) and 1 (yellow signal) on der(18) (see orange highlight) which indicates material of chromosome 10 (combined blue and green signal). D) The derivative chromosome 9 (combined red and yellow signal) of patient 2 shows an increase of the combined fluorochromes (blue and purple signals) used for chromosome 13 (see orange highlight), indicating a chromosome 13 insertion. Detection of the insertion of chromosome 5 in der(9) is more difficult with M-FISH, because of the combined colours red and yellow used for chromosome 9 in contrast to red used for chromosome 5, but a more intense fluorescent red signal over yellow is seen in the long arm of der(9). A diminished signal of red and yellow is present on the location of the insertion of chromosome 13.