FISH in a representative case of pseudomonosomy 7. Whole-chromosome painting (WCP) of a case in which CCA, but not sWGS, reported a monosomy 7. (A) WCP using a green probe mix targeting the whole chromosome 7, a red probe mix for whole chromosome 4, and a blue probe highlighting the centromere of chromosome 7 (chromosome enumeration probe [CEP]). Wild-type (WT) chromosomes 4 and 7 can be identified, as well as 2 derivative chromosomes (der) harboring some chromosome 7 material. (B) Corresponding sWGS profile along chromosome 7 shows that most of the chromosome was lost, whereas some segments are present or amplified, suggesting a complex rearrangement of 1 of the chromosomes 7 instead of a clean loss.