A NEW DISCOVERY IN GOLDEN RETRIEVER HEART HEALTH

On February 25, 2026, the Evergreen Golden Retriever Club welcomed Dr. Joshua Stern as our guest speaker for the general membership meeting. Dr. Stern serves on the OFA Board of Directors and is Associate Dean and Professor of Cardiology in Veterinary Medicine at North Carolina State University. Although based on the East Coast, he joined us virtually late in the evening from North Carolina to present groundbreaking research that changes how we think about inherited heart disease in Golden Retrievers.

Dr. Stern is not only a cardiologist and genetic researcher, he is also a Golden Retriever owner. His own dogs have participated in and supported numerous research studies

Hypertrophic cardiomyopathy (HCM) is most commonly recognized as a disease of cats and humans. It is characterized by abnormal thickening of the heart muscle, particularly affecting the left ventricle. This thickening restricts the heart’s pumping capacity and reduces oxygen delivery to cardiac tissue. Clinical consequences can include congestive heart failure, thromboembolic events, and sudden cardiac death. Importantly, some affected individuals may remain asymptomatic until advanced disease or sudden death occurs.

In humans, more than 50 mutations have been associated with HCM. In cats, three known mutations have been identified. Until recently, no definitive mutation had been characterized in dogs.

In September 2023, Dr. Stern was contacted regarding several Golden Retriever puppies that had died suddenly between 10 and 14 months of age. The deaths occurred in two separate litters from the same repeat breeding. Full necropsies were performed on the first three puppies, leading to the hypothesis of a genetic etiology.

Using whole genome sequencing,  a technology that has become dramatically more affordable in recent years, Dr. Stern and his graduate student, Victor, sequenced affected dogs and related family members. What might have cost tens of thousands of dollars a decade ago was completed for under $5,000.

Initial analysis identified approximately 13 million genetic variants. Through systematic filtering and statistical analysis, that number was reduced to roughly 100,000 variants of interest. Of those, approximately 200 affected protein function, and 33 were considered high impact. Ultimately, the team narrowed the candidates to ten potential mutations.

The causative mutation was identified in the cardiac troponin I gene, part of the thin filament complex critical to cardiac muscle contraction. This mutation segregated perfectly with affected dogs. In humans, mutations in this gene are associated with early-onset cardiomyopathy in adolescents and young adults.

Pedigree research traced the mutation back at least six generations to a likely common ancestor. The true origin beyond that point remains unknown. The depth of pedigree involvement suggests the possibility that some historical sudden deaths or early puppy losses may have been related to this mutation without being recognized as such.

Interestingly, even Dr. Stern’s own Golden Retriever was found to be a carrier, despite no reported heart disease in the immediate lineage. The current estimated allele frequency is approximately 4-7%. There also appears to be a second modifier mutation which, when present alongside the troponin I mutation, may increase disease severity. Dogs testing positive for the troponin I variant are eligible for additional testing for the modifier mutation at no additional cost. Carriers are not believed to be at risk of developing clinical disease.

Given the allele frequency and the potential for early lethality in affected puppies, Dr. Stern believes this is a test worth incorporating into breeding considerations.

Testing information and study participation details are available through North Carolina State University:

https://hospital.cvm.ncsu.edu/services/small-animals/genetics/golden-retriever-hcm/

Testing involves completing an online form then a swab kit is mailed directly to participants.

This discovery is a significant advancement in our understanding of cardiac disease in Golden Retrievers.As a club dedicated to preserving and improving the breed, EGRC encourages members to stay informed, consider participation in research initiatives, and engage in thoughtful dialogue about how new genetic information should be integrated into breeding decisions.

We extend our sincere thanks to Dr. Stern for sharing his time, expertise, and passion for Goldens with our membership.