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Genetics Research International
Volume 2011, Article ID 185271, 7 pages
http://dx.doi.org/10.4061/2011/185271
Case Report

Three Supernumerary Marker Chromosomes in a Patient with Developmental Delay, Mental Retardation, and Dysmorphic Features

1Pittsburgh Cytogenetics Laboratory, Magee-Womens Hospital of UPMC and Department of Obstetrics, Gynecology & Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
2Department of Pediatrics, University of Pittsburgh School of Medicine and Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15213, USA
3Pittsburgh Cytogenetics Laboratory, Magee-Womens Hospital of UPMC, Pittsburgh, PA 15213, USA
4Pittsburgh Cytogenetics Laboratory, Magee-Womens Hospital of UPMC and Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA

Received 16 February 2011; Revised 28 April 2011; Accepted 7 May 2011

Academic Editor: Reha Toydemir

Copyright © 2011 Jie Hu 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

We characterized three supernumerary marker chromosomes (SMCs) simultaneously present in a 2-year- and 10-month-old male patient with mental retardation and dysmorphic features. Peripheral blood chromosome analysis revealed two to three SMCs in 25/26 cells analyzed. The remaining one cell had one SMC. Microarray comparative genomic hybridization (aCGH) showed mosaicism for gains of 5q35.3, 15q11.2q13.3, and 18p11.21q11.1 regions. All three gains contain multiple OMIM genes. FISH studies indicated that one of the SMCs is a dicentric ring 15 with two copies of the 15q11.2q13.3 region including SNRPN/UBE3A and two copies of the 5q35.3 region. One of the der(18)s contains the 18 centromere and 18p11.2 regions, while the other der(18) has a signal for the 18 centromere only. The phenotype of the patient is compared with that of patients with tetrasomy 15q11.2q13.3, trisomy 5q35.3, and trisomy 18p11.2. Our study demonstrates that aCGH and FISH analyses are powerful tools, which complement the conventional cytogenetic analysis for the identification of SMCs.