Two familial intrachromosomal insertions with maternal dup(6)(p22.3p25.3) or dup(2)(q24.2q32.1) in recombinant offspring

In this study, we describe two patients with a recombinant chromosome secondary to a maternal intrachromosomal insertion. Patient 1 was a girl with dup(6)(p22.3p25.3). Patient 2 was a boy with dup(2)(q24.2q32.1). Both familial rearrangements were characterized by means of GTG-bands, fluorescence in-situ hybridization, and comparative genomic hybridization microarray analyses. Patient 1 had an ∼23 Mb gain that involved the bands 6p22.3-6p25.3. Patient 2 had an ∼23 Mb gain (cytobands 2q24.2–2q32.1) and a further ∼1.9 Mb gain of 2p16.2–p16.3. The phenotype of each patient was in agreement with the typical 6p duplication or 2q24.2q32.1 duplication syndrome. The compound macular lesion in patient 1 suggests that retinal anomalies may be a part of the 6p trisomy phenotype. Among the 70 intrachromosomal insertions compiled here (including 68 from the literature), four were submicroscopic unbalanced insertions inherited from a balanced carrier and 66 were detectable on banded chromosomes (with or without array comparative genomic hybridization or other high-resolution assessment) and therefore spanned at least 5 Mb. Pericentric insertions are found in most chromosomes, whereas the paracentric ones are mainly observed in large and medium chromosome arms. That the former outnumber the latter in almost a 2 : 1 ratio appears to be related to the technique of diagnosis, size of the insertion, and size of the involved chromosome. Regardless of the apparent excess of c...

Source: Clinical Dysmorphology - September 7, 2017 Category: Genetics & Stem Cells Tags: Original Articles Source Type: research