Chromosome painting using FISH (fluorescence in situ hybridization) with chromosome‐6‐specific library demonstrates the origin of a de novo 6q+ marker chromosome

Brøndum‐Nielsen K, Bajalica S, Wulff K, Mikkelsen M. Chromosome painting using FISH (fluorescence in situ hybridization) with chromosome‐6‐specific library demonstrates the origin of a de novo 6q+ marker chromosome. Clin Genet 1993: 43: 235–239. © Munksgaard, 1993 We report the application of chromosome painting using FISH (fluorescence in situ hybridization) to demonstrate the origin of a de novo 6q + marker chromosome. A girl with a mental retardation/multiple malformation syndrome was shown to have the karyotype 46,XX, 6q+. Banding analysis could not determine the origin of the extra chromosomal material. Using FISH with a chromosome‐6‐specific library we showed that the marker chromosome was completely painted, indicating an origin from chromosome 6. The child's phenotype was compared with previously reported cases with partial chromosome 6 trisomy. A clinically recognized syndrome emerged, although she apparently also demonstrated novel features.