Trisomy 2q35-q37 due to insertion of 2q material into 17q25: Clinical, cytogenetic, and molecular cytogenetic characterization

We present a 7-year-old boy with growth retardation, developmental and ment al delay, and minor physical abnormalities. The patient had a male karyotyp e with duplicated material of unknown origin in the long arm of chromosome 17, The origin of the duplicated material was clarified by fluorescence in situ hybridization, Forward chromosome painting showed that the extra mater ial originated from chromosome 2, which was inserted into 17q25, Further ch aracterization of the aberrant chromosome 17 by microdissection and reverse chromosome painting revealed a duplication of bands 2q35 to q37.1. To our knowledge, no other individual with a duplication of this small segment has been described so far. The clinical findings of 13 cases with isolated tri somy 2q are reviewed in relation to the size of the duplicated region, Func tional analysis of the duplicated 2q region suggests that critical loci for visceral and central nervous system development in distal trisomy 2q are p roximal to 2q33. (C) 1999 Wiley-Liss, Inc.