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 nov
o 6q+ marker chromosome. A male patient with peculiar features of "distal 6
q trisomy syndrome" showed a direct duplication of 6q23 region. Comparing t
he 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 t
risomy.