Glossary of Terms

The following terms are important to understanding the health and structural defects targeted by the Project.

• IVDD /CDDY – CDDY (Chondrodystrophy) and IVDD (Intervertebral Disc Disease) are closely related conditions in dogs. CDDY is a genetic condition that causes shortened limbs and predisposes dogs to IVDD, a painful and potentially debilitating spinal disorder. IVDD occurs when the cushioning discs between vertebrae degenerate and either bulge or rupture, compressing the spinal cord.
• MVD heart disease -Mitral Valve Disease (MVD) is a serious health concern for Cavalier King Charles Spaniels, significantly impacting their heart health. MVD is a progressive heart condition where the mitral valve, which regulates blood flow between the heart’s left atrium and ventricle, degenerates. This degeneration causes the valve to leak, leading to mitral regurgitation and potentially congestive heart failure. Most Cavaliers have MVD.
• SM/CM – in Cavalier King Charles Spaniels, SM refers to Syringomyelia, a neurological condition characterized by fluid-filled cavities (syrinxes) forming in the spinal cord. It’s often associated with Chiari-like malformation (CM), where the skull is too small, causing spinal fluid to be forced into the spinal cord. This can lead to pain, scratching, and other neurological symptoms. Most Cavaliers have CM, over half the populations has SM.
• COI -in genetics, COI stands for Coefficient of Inbreeding. It’s a statistical measure that quantifies the likelihood of an individual inheriting the same gene from both parents, due to those parents sharing common ancestors. A higher COI indicates a greater degree of inbreeding, while a lower COI suggests more genetic diversity. All pure-bred Cavaliers have a COI over 25%, the majority at 35%. For reference the offspring of full siblings is 25%.
• Runs of Homozygosity (ROH): These are contiguous stretches of DNA in an individual’s genome where both copies of the chromosomes (one from each parent) are identical by descent (IBD), meaning they originated from a common ancestor. ROH arise when individuals inherit identical haplotypes from their parents, which is particularly common in the offspring of closely related individuals. The length and number of ROH reflect the history of inbreeding and population demographics, with longer ROH indicating more recent inbreeding.
• Brachycephalic- Cavalier King Charles Spaniels are considered a brachycephalic breed, meaning they have a shortened skull and muzzle, which can lead to breathing difficulties. While their muzzle isn’t as short as some other brachycephalic breeds, they can still experience health issues related to their head shape, including Brachycephalic Airway Obstruction Syndrome (BAOS). The main concern for Cavaliers and being Brachy is lack of head space. Their brain is too large for their skull, causing pain from CM / SM
• FDC, Functional Dog Collaborative supports the ethical breeding of healthy and behaviorally sound dogs
• AKC is the largest pure-bred dog kennel club registry for the USA
• UKC is the second largest pure-bred dog kennel club registry for the USA
• KC, The Kennel Club, is the UK kennel club, the original
• FCI is the world-wide governing dog registry for most countries
• OFA is a USA based health data registry
• OFA CHIC is a status of achieved full disease testing as prescribed for each dog breed. Each AKC breed club sets the standard of testing for their breed.
• Embark Genetics is a USA based DNA company screening dogs for diseses, traits and COI inbreeding data
• CAER is the eye registry for veterinary ophthalmologist to use for eye conditions, the data is recorded with OFA
• Auscultation – the action of listening to sounds from the heart, lungs, or other organs, typically with a stethoscope, as a part of medical diagnosis.
• Echocardiogram (Echo) is a non-invasive imaging test that uses ultrasound waves to create detailed pictures of the heart. It provides information about the heart’s structure, function, and blood flow. 

Join the Companion Dog Project and Registry

You can join the mission of the Cavalier Improvement Project by joining the Companion Dog Project and the Companion Dog Registry.