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Case Reports in Genetics
Volume 2014, Article ID 516529, 9 pages
Case Report

Absence of Substantial Copy Number Differences in a Pair of Monozygotic Twins Discordant for Features of Autism Spectrum Disorder

1Human Genetic Unit, Department of Basic Medical Sciences, University of Lleida, 25198 Lleida, Catalonia, Spain
2Genetics of Complex Diseases Research Group, Biomedical Research Institute of Lleida (IRBLleida), 25198 Lleida, Catalonia, Spain
3Biological-Factorial Models of Personality, Department of Psychology, University of Lleida, 25001 Lleida, Catalonia, Spain
4Clinical Analysis Service, Universitari Arnau de Vilanova University Hospital, 25198 Lleida, Catalonia, Spain
5Department of Genetics, Son Espases University Hospital, 07120 Palma de Mallorca, Spain

Received 18 September 2013; Accepted 20 October 2013; Published 19 January 2014

Academic Editors: M. G. Kibriya and T. Kubota

Copyright © 2014 Marina Laplana 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.


Autism spectrum disorder (ASD) is a highly heritable disease (~0.9) with a complex genetic etiology. It is initially characterized by altered cognitive ability which commonly includes impaired language and communication skills as well as fundamental deficits in social interaction. Despite the large amount of studies described so far, the high clinical diversity affecting the autism phenotype remains poorly explained. Recent studies suggest that rare genomic variations, in particular copy number variation (CNV), may account for a significant proportion of the genetic basis of ASD. The use of disease-discordant monozygotic twins represents a powerful strategy to identify de novo and inherited CNV in the disorder. Here we present the results of a comparative genome hybridization (CGH) analysis with a pair of monozygotic twins affected of ASD with significant differences in their clinical manifestations that specially affect speech language impairment and communication skills. Array CGH was performed in three different tissues: blood, saliva, and hair follicle, in an attempt to identify germinal and somatic CNV regions that may explain these differences. Our results argue against a role of large CNV rearrangements as a molecular etiology of the observed differences. This forwards future research to explore de novo point mutation and epigenomic alterations as potential explanations of the observed clinical differences.