Tricuspid valve dysplasia (TVD)
Research/Funding Project

The Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania, through Dr. Meg M. Sleeper, VMD, DACVIM-Cardiology, Petra Werner, DVM and Paula Henthorn PhD, is interested in continuing the TVD research.

Currently they are collecting clinical and pedigree data and blood for DNA isolation from affected dogs, littermates, parents and grandparents. They plan to continue this research with the goal to be able to offer a DNA based test for the disease in the future. If there is enough interest in the Labrador Breed Organizations, they will perform further research as money becomes available. The estimated cost for DNA isolation, initial sample analysis, and salary support for one year would be approximately $50,000.

Tricuspid valve dysplasia (TVD) in dogs is similar to Ebsteinís anomaly in humans. Both disorders involve congenital malformations of the tricuspid valve, which result in variable degrees of tricuspid valve regurgitation (TR). Dogs with the most severe TR or tricuspid stenosis will typically develop right-sided congestive heart failure within the first few years of life. The pathogenesis of tricuspid valve malformation is largely unknown. Many dogs are only mild to moderately affected, and are not identified until after they have become breeding animals. Labrador Retrievers, in particular, seem to be predisposed to TVD.

A previous study evaluated several kindreds of Labrador Retrievers, and determined, through clinical cardiology examinations, pedigree analysis, and genetic analysis, that TVD is inherited as an autosomal dominant trait with incomplete penetrance. Genetic analysis of dogs in the same study mapped a susceptibility locus to canine chromosome 9 (CFA9). It is crucial to continue to examine Labrador retriever kindreds through clinical cardiology examinations, pedigree analysis, and genetic analysis for the future identification of a mutant allele of a gene or genes responsible for TVD. Once found, genetic testing procedures can be developed, which will allow earlier identification of dogs at risk for developing clinical signs, and at risk of passing the disease to their offspring.

A reliable test for identifying affected dogs not only in Labrador Retrievers but in additional dog breeds, will allow breeders to markedly decrease the prevalence of this often devastating congenital heart defect.

In order to further the research to find the TVD causing mutation they need:

1) Information and samples of either individual affected dogs or preferably as many dogs as possible (affected and unaffecteds) from families with affected members. (Affected dogs, littermates, parents and grandparents) They would like pedigree information, the clinical history,diagnosis, and blood samples (5 to 10 ml of EDTA blood) for DNA isolation. Also, cardiology evaluations on any of these related dogs.

Dr. Sleeper has said that everything is confidential. Sending blood, pedigree and cardio report from affected dogs would be great and they can be stored until funding is available (no charge).

Please send 5 mls in a purple top tube (that is EDTA, not heparin) and the resulting whole blood does not need to be separated. The tube(s) should be sent with a cool pack and in a zip lock bag so if anything breaks blood will not damage the papers enclosed (pedigree and cardio reports).

Checks for TVD Research should be made out to "Trustees of the University of Pennsylvania" and in the memo put TVD study and send to Meg Sleeperís at the below address.

Samples and reports should be sent to:

Meg Sleeper, VMD, DACVIM-Cardiology
Section of Cardiology
MJR-VHUP
3900 Delancey Street
Philadelphia, PA 19104
sleeper@vet.upenn.edu

Please also visit the NLRC website for further information about TVD Research and Funding.