Trisomy 6q syndrome: a case with a << de novo >> 6q23 tandem duplication.

In this study, we report the combined use of whole and partial chromosome 6 painting probe and YACS probes to define the unbalanced region of a de novo 6q+ marker chromosome. A male patient with peculiar features of << distal 6q trisomy syndrome >> showed a direct duplication of 6q23 region. Comparing the phenotype of this child with the phenotype of other << de novo >> partial 6q trisomy, we conclude that band 6q23 has an important role in defining 6q trisomy.