DETECTION OF A CONCOMITANT DISTAL DELETION IN AN INVERTED DUPLICATIONOF CHROMOSOME-3 - IS THERE AN OVERALL MECHANISM FOR THE ORIGIN OF SUCH DUPLICATIONS DEFICIENCIES/

We describe the first inverted duplication of the p21.3p26 region of c hromosome 3 in a child with phenotypic features of the trisomy 3p synd rome. This uncommon type of aberration was verified by multicolour flu orescence in situ hybridisation (FISH) using yeast artificial chromoso me (YAC) clones from chromosome 3 (CEPH library). With a newly constru cted YAC clone from the 3p26 region an unexpected subtelomeric deletio n was diagnosed in the aberrant chromosome 3. Using the primed in situ labelling (PRINS) method, telomeres were found to be present on the r ecombinant chromosome 3. The repeated appearance of concomitant distal deletions in inverted duplications suggests that an overall mechanism exists for the origin of such duplications/deficiencies.