CHARACTERIZATION OF DENOVO DUPLICATIONS IN 8 PATIENTS BY USING FLUORESCENCE INSITU HYBRIDIZATION WITH CHROMOSOME-SPECIFIC DNA LIBRARIES

Fluorescence in situ hybridization (FISH) with chromosome-specific DNA libraries was performed on samples from eight patients with de novo c hromosomal duplications. In five cases, the clinical phenotype and/or cytogenetic evaluations suggested a likely origin of the duplicated ma terial. In the remaining three cases, careful examination of the GTG-b anding pattern indicated multiple possible origins; hybridization with more than one chromosome-specific library was performed on two of the se cases. In all cases, FISH conclusively identified the chromosomal o rigin of the duplicated material. In addition, the hybridization patte rn was useful in quantitatively delineating the duplication in two cas es.