NEBL3 (often referred to informally as AG or GG) is a gene currently under investigation for its possible association with improved heart health in Cavalier King Charles Spaniels, particularly in relation to Mitral Valve Disease (MVD).

Importantly, NEBL3 is not a guarantee of protection. At this stage, it is best described as a potential marker that requires ongoing investigation, long-term tracking, and responsible interpretation. Genetics are only one piece of a much larger puzzle. No single gene determines health outcomes on its own.

A Science-Led Approach — Not a Promise

• NEBL3 testing does not replace:
• Regular cardiologist heart examinations
• Long-term health tracking
• Responsible breeding decisions
• Environmental, nutritional, and lifestyle considerations

What NEBL3 offers is a research opportunity, not a shortcut. The value of this gene can only be understood through real-world data — following dogs throughout their lives, across generations, and in combination with established veterinary science.

Why Tracking Matters

For any genetic marker to be meaningful, it must be:

• Tracked over time
• Linked to clinical outcomes
• Supported by pedigree data
• Measured alongside known health results

This is why simply testing for a gene is not enough.

Our Commitment to Evidence-Based Breeding

Through our broader Healthy Hearts Project, our commitment goes beyond a single test. We actively:

• Research and document pedigrees over multiple generations
• Track longevity, heart health, and quality of life
• Record dogs with late onset, mild, or no heart disease
• Identify and log lines with known or emerging health concerns
• Share data responsibly to contribute to breeding science

This includes acknowledging what we don’t yet know, and being transparent about limitations.

Linking Genetics With Breeding Science

NEBL3 is being explored within this framework — not in isolation. Only by combining:

• Genetic data
• Clinical heart testing
• Pedigree analysis
• Lifelong follow-up

can we determine whether NEBL3 has true predictive value.

Looking Forward

Progress in breed health comes from:

• Collaboration, not claims
• Data, not assumptions
• Transparency, not guarantees

Our goal is simple but serious: to contribute responsibly to the long-term heart health of Cavaliers, using science, patience, and integrity.