IDENTIFICATION AND CHARACTERIZATION OF A DE-NOVO PARTIAL TRISOMY 10P BY COMPARATIVE GENOMIC HYBRIDIZATION (CGH)

We report the characterization of a de noaa unbalanced chromosome rear rangement by comparative genomic hybridization (CGH) in a 15-day-old c hild with hypotonia and dysmorphia. We describe the combined use of CG H and fluorescence in situ hybridization (FISH) to identify the origin of the additional chromosomal material on the short arm of chromosome 6. Investigation with FISH revealed that the excess material was not derived from chromosome 6. Identification of unknown unbalanced aberra tions that could not be identified by traditional cytogenetics procedu res is possible by CGH analysis. Visual analysis of digital images fro m CGH-metaphase spreads revealed a predominantly green signal on the t elomeric region of chromosome 10p. After quantitative digital ratio im aging of 10 CGH-metaphase spreads, a region of gain was found in the c hromosome band 10p14-pter. The CGI-I finding was confirmed by FISH ana lysis, using a whole chromosome 10 paint probe. These results show the usefulness of CGH for a rapid characterization of de novo unbalanced translocation, unidentifiable by karyotype alone.