Duplication within chromosome 5q characterized by fluorescence in situ hybridization

We present a 16-month-old boy with developmental delay, minor anomalies, sm all penis, and lymphedema of the upper limbs. Routine cytogenetic analysis suspected a duplication of 5q, Fluorescent in situ hybridization (FISH) wit h a cosmid probe (MCC at the 5q22 APC region) showed tandemly duplicated fl uorescent signals on one of chromosomes 5, whereas FISH with three YAC prob es (TYAC12 at 5q35, HTY3182 at 5q34, and TYAC139 at 5q31) did not give dupl icated signals. These findings indicate a duplication of 5q22 band in one c hromosome 5, The boy we describe here is the first case of a pure partial d uplication of 5q to be proven by FISH techniques. A review of previously re ported cases of putative partial 5q duplication showed no consistent phenot ype. Am. J, Med, Genet. 83:361-364, 1999. (C) 1999 Wiley-Liss, Inc.