Short reportInherited 18q23 duplication in a fetus with multiple congenital anomalies
Introduction
Unbalanced submicroscopic telomere rearrangements are a significant cause of congenital malformations/mental retardation syndromes, accounting for approximately 5% of these cases [9], [15], [22]. Telomeric imbalances have also been identified inherited from a phenotypically normal parent carrying the same deletion or duplication, thus without apparent phenotypic effect [1], [2], [3], [14]. For many of the telomere imbalances the genotype/phenotype correlations has not clearly been established, complicating the diagnostic and prognostic implications. Further reports are thus needed for all telomeric regions to define how much monosomy or trisomy can be tolerated without phenotypic effect and, conversely, how much monosomy or trisomy will have a phenotypic effect.
In this report, we examine a fetus containing multiple congenital anomalies with an 18q23 duplication inherited from its healthy father. We describe the anomalies identified, discuss diagnosis, and the causability of this subtelomeric duplication.
Section snippets
Clinical data
The patient was the first child of an unrelated Caucasian couple with an unremarkable family history. Fetal ultrasound performed at 20 weeks of gestation showed complete corpus callosum agenesis, cerebellar hypoplasia, Dandy Walker malformation, and retrognathism. The couple was informed of the cerebral malformation and the associated poor prognosis. The pregnancy was terminated at 23 weeks of gestation. Necropsy showed a very hairy female fetus with a large anterior fontanel, short nose,
Discussion
No copy number variants (CNV) have been described in this region in the recent article by Redon et al. [21]. To our knowledge, an overlapping CNVs has only been reported at once in the Database of Genomic Variants (http://projects.tcag.ca/variation/). This CNV was reported by Zogopoulos et al. [28] who reported a very large 18q duplication (3,932,849 bp) with starting position 72,182,705 Mb to 76,115,554 Mb.
Phenotype in individuals with partial duplication of the long arm of chromosome 18 is
Electronic database information
Chromosome Anomaly Collection, http://www.ngrl.org.uk/wessex/collection
Database of Genomic Variants, http://www.projects.tcag.ca/variation
ECARUCA, http://www.ecaruca.net
Human Genome Browser, May 2004 Freeze, http://www.genome.ucsc.edu
Human Genome Segmental Duplication Database, http://www.projects.tcag.ca/humandup
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