963: Genotyping Small Breed Dogs with Portosystemic Vascular Anomalies and Microvascular Dysplasia

Grant Amount: $189,489

Sharon A. Center, DVM; Cornell University

June 1, 2008 - December 31, 2011

Sponsor(s): American Cavalier King Charles Spaniel Club Charitable Trust, Cavalier King Charles Spaniel, USA Health Foundation

Breed(s): Maltese, Shih Tzu, Havanese, Tibetan Spaniel, Cairn Terrier, Yorkshire Terrier

Research Program Area: Hepatic Disease

Abstract

Background: Portosystemic vascular anomalies (PSVA) and microvascular dysplasia (MVD) are related genetic disorders causing malformation of the liver circulation. This trait affects a number of small pure breed dogs, causing high serum bile acid values (SBA) and has a prevalence ranging from 30% to 80% in various breeds and related dogs. Objective: The goal is to identify a genetic marker for PSVA/MVD that will allow development of a genetic test. Extensive pedigree studies support an autosomal dominant but incompletely penetrant mode of transmission, explaining the dismal success of attempted trait elimination based on SBA. It is important to eliminate this trait because affected dogs cause owner dissatisfaction, financial burden, and negative breed publicity, in addition to patient suffering. The researchers have discovered significant linkage between the PSVA/MVD trait and genetic markers on one chromosome in a large family of Tibetan Spaniels. Findings have been confirmed with flanking markers and demonstration of similar linkage in Cairn Terriers, Maltese, and Havanese. The researchers will pursue further genetic mapping (microsatellites, SNPs) of the PSVA/MVD trait in these and additional breeds, and undertake association mapping using DNA banked from unrelated pure breed dogs with PSVA (n=70). Candidate genes associated with abnormal vascular development in humans will be explored.

Publication(s)

None at this time.