Understanding the limitations of routine genetic testing protocols is of critical importance for the clinician. Standard DNA sequencing protocols are a reliable method for the detection of single point mutations or small insertions and deletions. However, these protocols cannot detect the presence of large genomic rearrangements that might affect culprit genes. This failure might lead to the questioning of a diagnosis, or prevent familial cascade screening. We present the first report of a large genomic duplication affecting the KCNQ1 gene in a patient with a robust phenotype of long QT syndrome who was first reported to have negative genetic results.
Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.