FISH analysis in detecting 9p duplication (p22p24).

Authors report on a case of partial 9p duplication, involving the 9p22-9p24 region. This represents the second case of such duplication in which the breakpoints were precisely defined using fluorescence in situ hybridisation (FISH) with chromosome 9 specific painting and YAC DNA probes, localised onto 9p22-9p24 region. FISH analysis pinpointed chromosome breakpoints in dup(9)(p22p24) and excluded an insertion or a translocation from other chromosomes. The present report supports the segment 9p22-9p24 as the critical region for the observed phenotype of the duplication 9p syndrome.