A case report of de novo 11q triplication, duplication, and segmental area of absence of heterozygosity in an infant with dysmorphic features, failure to thrive, and developmental delay.

Abstract

Background With recent advances in array comparative genomic hybridization (aCGH) methods, several, previously unrecognized pathogenic copy number variants (CNVs) have been recognized. Intrachromosomal triplications are rare and have been reported in a few genomic regions. In this report, we describe an infant with complex chromosomal rearrangement involving the long arm of chromosome 11 with concomitant triplication, duplication, and segmental area of absence of heterozygosity (AOH). Case Presentation: We report an infant who was presented with dysmorphic features, severe failure to thrive, developmental delay, dysgenesis of the corpus callosum, and intestinal obstruction. The aCGHshowed 19,930 megabases (Mb) triplication at 11q13.3q14.3, 346 kilobases(Kb) duplication at 11q14.3 and an area of AOH at 11q14.3-qter. Conclusion The occurrence of triplication along with AOH (most likely as a result of segmental uniparental isodisomy) is a rare, complex genomic rearrangement. It is suggested that these complex genomic rearrangements coupled with segmental uniparental isodisomy arise as a result of one-ended DNA break repair coupled with microhomology-mediated break-induced replication (MMBIR).