03134: Use of a Service Dog Breeding Program to Unravel the Genetics of Congenital Idiopathic Megaesophagus in German Shepherd Dogs

One Health: Yes

Abstract

Congenital idiopathic megaesophagus (CIM) is characterized by an enlarged esophagus and ineffective swallowing. Affected puppies are unable to pass food into their stomachs, regurgitate meals and water, and show a failure to thrive. Survivors are susceptible to aspiration pneumonia and intussusception. CIM affects all breeds, but German Shepherd Dogs (GSDs) by far have the highest prevalence. CIM is genetically complex, and this research team previously showed that females have a protective biological advantage. Through a genome-wide scan, the team has also determined that MCHR2 is a major locus underlying genetic risk in the GSD. However, the risk allele is common among healthy dogs, making it challenging for breeders to select against it. Here, investigators hypothesize that we can find additional risk factors in a breeding program of assistance GSDs. The Seeing Eye breeds GSDs to be guides for the blind and visually impaired. They maintain detailed health and genetic records, store biologic material in a biobank, and thoroughly phenotype every puppy for CIM. This breeding program provides a unique opportunity to utilize sibling pairs to identify genomic loci that differ between affected and healthy siblings. Associated variants will be incorporated into the current risk assessment to help breeders reduce the incidence of CIM while maintaining genetic diversity and desirable phenotypes. 

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