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Case Reports in Genetics
Volume 2013, Article ID 578202, 3 pages
http://dx.doi.org/10.1155/2013/578202
Case Report

First Trimester Diagnosis of Holoprosencephaly Secondary to a Ring Chromosome 7

1Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
2Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
3Department of Pathology, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Park Building SB202, Baltimore, MD 21287, USA
4Cytogenetics Laboratory, Kennedy Krieger Institute, Baltimore, MD 21287, USA

Received 31 December 2012; Accepted 21 January 2013

Academic Editors: M. Chikri, P. Morrison, and C. Yapijakis

Copyright © 2013 Lindsay B. Henderson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Holoprosencephaly (HPE) is a developmental defect in humans in which the forebrain fails to completely separate into two hemispheres. We describe a 12 3/7-week-old fetus found on ultrasound evaluation to have features consistent with HPE, including a single anterior ventricle, fused thalami, and a flattened profile. Cytogenetic analysis of chorionic villi revealed a ring chromosome 7 [r(7)]. This uncommon finding has been associated with growth delay, microcephaly, and dermatologic abnormalities. However, both the clinical features and the extent of cytogenetic imbalance of chromosome 7 are variable, and few reported cases of r(7) have been molecularly studied. To our knowledge, this is the first report of a prenatally identified r(7), molecularly characterized using array comparative genomic hybridization.