A patient with an interstitial duplication of chromosome 5p11-p13.3 further confirming a critical region for 5p duplication syndrome.

Partial or complete trisomy 5p has been associated with characteristic facial features, developmental delay, seizures, congenital heart defects, and respiratory compromise. We present a child with developmental delay, seizures, and congenital cardiac anomalies found to have a previously unreported de novo interstitial duplication of chromosome 5p, 46,XX,dup(5) (p11p13.3). The breakpoints of the duplication were further confirmed by fluorescence in situ hybridization analysis using bacterial artificial chromosome probes specific for the affected region. Comparison with previously reported cases of patients with duplications of 5p suggests loci of interest for both congenital heart anomalies and seizures.