Sudden death associated with QT interval prolongation and KCNQ1 gene mutation in a family of English Springer Spaniels

Ware, W.A., Reina Doreste, Y., Stern, J.A. and Meurs, K.M. (2015) Sudden death associated with QT interval prolongation and KCNQ1 gene mutation in a family of English Springer Spaniels. Journal of Veterinary Internal Medicine, 29(2), pp. 561-568. (doi: 10.1111/jvim.12550) (PMID:25779927) (PMCID:PMC4895492)

Abstract

Background: A 5-year-old, healthy English Springer Spaniel died suddenly 4 months after delivering a litter of 7 puppies. Within 4 months of the dam's death, 3 offspring also died suddenly. Hypothesis: Abnormal cardiac repolarization, caused by an inherited long QT syndrome, is thought to be responsible for arrhythmias leading to sudden death in this family. Animals: Four remaining dogs from the affected litter and 11 related dogs. Methods: Physical examination and resting ECG were done on the littermates and 9 related dogs. Additional tests on some or all littermates included echocardiogram with Doppler, Holter monitoring, and routine serum biochemistry. Blood for DNA sequencing was obtained from all 15 dogs. Results: Three of 4 littermates examined, but no other dogs, had prolonged QT intervals with unique T-wave morphology. DNA sequencing of the KCNQ1 gene identified a heterozygous single base pair mutation, unique to these 3 dogs, which changes a conserved amino acid from threonine to lysine and is predicted to change protein structure. Conclusions and Clinical Importance: This family represents the first documentation in dogs of spontaneous familial QT prolongation, which was associated with a KCNQ1 gene mutation and sudden death. Although the final rhythm could not be documented in these dogs, their phenotypic manifestations of QT interval prolongation and abnormal ECG restitution suggested increased risk for sudden arrhythmic death. The KCNQ1 gene mutation identified is speculated to impair the cardiac repolarizing current IKs, similar to KCNQ1 mutations causing long QT syndrome 1 in humans.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Reina Doreste, Mr Yamir
• Authors: Ware, W.A., Reina Doreste, Y., Stern, J.A., and Meurs, K.M.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Journal of Veterinary Internal Medicine
• Publisher: American College of Veterinary Internal Medicine.
• ISSN: 0891-6640
• ISSN (Online): 1939-1676
• Published Online: 16 March 2015
• Copyright Holders: Copyright © 2015 The Authors
• First Published: First published in Journal of Veterinary Internal Medicine 29(2):561-568
• Publisher Policy: Reproduced under a Creative Commons License