Genetic Testing for Cavalier King Charles Spaniels: Available DNA Tests & What They Mean

Genetic testing for Cavaliers: what this article covers

This article explains the DNA tests currently available that are relevant to [Cavalier King Charles](https://seniorpet.org/knowledge/breed/cavalier-king-charles-spaniel "Senior Cavalier King Charles Spaniel Health Guide") Spaniels (CKCS), what each test result means for owners and breeders, and how DNA testing fits with clinical screening (echocardiography for [mitral valve disease](https://seniorpet.org/knowledge/cavalier-king-charles-spaniel-mitral-valve-disease "Mitral Valve Disease Guide") and MRI for Chiari-like malformation / syringomyelia). It is focused specifically on Cavalier King Charles Spaniels and integrates breed-specific screening recommendations, testing laboratories and approximate costs, and pragmatic breeding guidance.

Key Statistics & Research Data

• Lifetime risk of myxomatous mitral valve disease (MMVD) in CKCS is extremely high; epidemiologic reports and specialty guidelines describe that a large majority of CKCS develop audible mitral valve disease by middle age, with prevalence estimates often cited as >50% by 5–6 years and >90% by 9–10 years in some cohorts (ACVIM consensus; breed studies) [1,2].
• Chiari-like malformation (CM) and syringomyelia (SM) are common and clinically relevant in CKCS; MRI screening programs (BVA/KC scheme) detect SM lesions in a sizable subset of CKCS, with variable prevalence reported depending on population and imaging protocol (screening data available through BVA/KC and breed clubs) [3].
• The SOD1 (c.118G>A) variant associated with degenerative myelopathy (DM) is present in CKCS; testing for SOD1 is widely available and used in breeding programs to reduce risk (Awano et al., 2009; OFA SOD1 database) [4,5].
• A BCAN gene variant has been associated with Episodic Falling Syndrome (EFS) in CKCS; a commercial test is available to identify carriers and affected dogs so breeder decisions can prevent affected puppies [6].
• A beta-1 tubulin (TUBB1) variant has been identified in CKCS and is associated with macrothrombocytopenia (large platelets with low platelet count). Most affected Cavaliers are clinically tolerant (few bleeding problems) but the abnormal platelet indices are important for clinical interpretation and for breeding decisions [7].
• Curly Coat / Dry Eye syndrome (CCDE) in CKCS has been linked to a FAM83H-associated variant in the breed and a DNA test exists to identify risk genotypes in potential breeding stock [8].
• Typical single-gene commercial test costs: $50–$160 per gene; multi-gene or expanded panels (Embark, Wisdom Panel, larger academic labs) typically $149–$350 depending on kit and report scope [9].
• Cardiology screening (auscultation + echocardiogram by a board-certified cardiologist) usually ranges $300–$900 depending on clinic and region; MRI for CM/SM typically ranges $1,500–$6,000 depending on anesthesia, sequences, and hospital [3,9].

Sources: ACVIM consensus statement on MMVD in dogs (2019), OFA SOD1 database and testing pages, UC Davis Veterinary Genetics Laboratory (VGL) service pages, BVA/KC Chiari & SM screening scheme, Embark and commercial lab pricing pages. See References for links and further reading [1–9].

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At-a-glance table: CKCS DNA tests, what they detect, and practical implications

| Condition (common name) | Gene typically tested | Inheritance pattern (breed-specific) | What a positive result means | Typical labs offering test | Typical cost (USD) | |---|---:|---|---|---|---:| | Episodic Falling Syndrome (EFS) | BCAN (identified BCAN variant) | Autosomal recessive (breed reports) | Homozygotes = affected (clinical episodes possible); heterozygotes = carriers (clinically normal). Prevent breeding carrier×carrier. | UC Davis VGL, Embark, Animal Genetics | $60–$150 | | Curly Coat / Dry Eye syndrome (CCDE) | FAM83H (breed-associated variant) | Autosomal recessive (reported in CKCS) | Homozygotes = higher risk of hair/ocular surface problems; carriers clinically normal. Important for breeder mate choice. | VGL, Embark, select specialty labs | $60–$150 | | Macrothrombocytopenia (platelet size/number) | TUBB1 (beta-1 tubulin) | Often autosomal dominant (breed-specific expression) | Dogs with variant often have low platelet counts and large platelets but are frequently asymptomatic. Important to flag for surgery/meds and for breeding decisions. | VGL, Embark, Animal Genetics, OFA platelet registry | $50–$150 | | Degenerative myelopathy (DM) | SOD1 (c.118G>A) | Complex; homozygotes (A/A) have increased risk; heterozygotes (G/A) have intermediate/increased risk depending on breed and modifiers | A/A dogs have the highest reported risk for DM onset; carriers (G/A) may develop DM at lower frequencies. Use test plus family history in breeding decisions. | OFA (accepts results), VGL, Embark, many labs | $40–$100 | | Myxomatous mitral valve disease (MMVD / MVD) | No single causative gene identified (polygenic) | N/A | There is no single DNA test that predicts MMVD risk. Clinical screening (auscultation + echocardiography) remains the standard for MVD risk assessment. | Cardiology clinics (echo), no DNA test | Echo costs $300–$900 |

Notes: Costs and lab listings are estimates and will vary by country and clinic. Some labs bundle multiple tests in panels; academic VGL labs may provide clinical-grade tests and reporting.

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The specific DNA tests: what each detects, accuracy, and clinical relevance for Cavaliers

1) Episodic Falling Syndrome (BCAN)

• What it is: EFS in CKCS is a paroxysmal movement disorder characterized by episodes of stiffness, collapsing without loss of consciousness, often precipitated by excitement or exercise. A BCAN variant was identified that is highly associated with the classical EFS phenotype in affected Cavaliers.
• Test: Genotyping for the BCAN deletion/variant identifies clear, carrier, and affected genotypes.
• Interpretation:

- Clear/Normal (no mutant allele): dog is not at genetic risk of producing affected puppies due to this variant. - Carrier (one mutant allele): dog is asymptomatic but will pass the allele to ~50% of offspring; carrier×carrier matings can produce affected puppies. - Affected (two mutant alleles): dog likely to show EFS signs (variable age of onset and severity).

• Clinical impact: For pet owners, a BCAN-affected dog requires symptomatic management (avoid triggers; consult neurology). For breeders, avoid mating two carriers; ideal approach is to use clear mates and, if using a carrier to preserve other traits, ensure no carrier mates.

2) Curly Coat / Dry Eye Syndrome (FAM83H)

• What it is: In CKCS, a syndrome combining an abnormal coat texture with tear film/ocular surface issues has been linked to a variant in FAM83H in the breed. Affected puppies may have hair/coating differences and ocular surface disease that can affect comfort and vision.
• Test & interpretation: Similar to typical recessive testing—clear, carrier, affected. Carriers are clinically normal but at risk of producing affected pups if bred to another carrier.
• Clinical impact: Ocular surface disease can be chronic; early ophthalmology involvement helps manage tear deficiencies and corneal health. Breeders should avoid carrier×carrier matings.

3) Macrothrombocytopenia (beta-1 tubulin / TUBB1)

• What it is: Macrothrombocytopenia in CKCS refers to conspicuously large platelets and low platelet counts associated with a TUBB1 variant. Most Cavaliers with the genotype are clinically well and do not have bleeding tendencies, but platelet counts measured by automated analyzers will often be low and blood smear evaluation shows giant platelets.
• Test interpretation:

- Presence of the variant predicts abnormal platelet indices (large platelets, low automated count). - Heterozygotes often show hematologic phenotype; inheritance pattern is usually dominant or semi‑dominant in dogs—meaning one copy can produce an abnormal lab result.

• Clinical relevance: Important for veterinarians planning surgery or starting medications that affect hemostasis. For breeders, knowledge of genotype prevents accidental production of puppies that could complicate clinical care, and some registries advise documenting status when breeding.

4) Degenerative Myelopathy (SOD1)

• What it is: DM is a progressive, late-onset spinal cord disease causing hindlimb weakness and paralysis. The SOD1:c.118G>A mutation is strongly associated with DM in multiple breeds, including CKCS, but disease penetrance is variable and influenced by other genetic and environmental factors.
• Test interpretation:

- A/A (two copies of the A variant): highest genotype-associated risk for DM; many but not all homozygotes develop clinical DM in middle to older age. - G/A (heterozygote/carrier): in some breeds heterozygotes appear at increased risk compared with G/G, but risk is lower than A/A; penetrance and age-of-onset vary. - G/G (clear): no SOD1 variant detected; DM risk from this SOD1 mutation is negligible.

• Clinical relevance: Because age of onset is typically older (often >8 years in many breeds), SOD1 results are used in breeding programs to reduce risk over generations, and to inform owners about potential late-onset neurologic monitoring. For pet owners, a positive SOD1 result does not mean imminent disease but indicates elevated lifetime risk.

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Cardiac screening in Cavaliers — why DNA testing does NOT replace heart exams

• Myxomatous mitral valve disease (MMVD / MVD) in CKCS is complex, strongly heritable but polygenic, and influenced by non-genetic factors. There is currently no validated single-gene DNA test that predicts MMVD risk in CKCS.
• Recommended cardiac protocol for CKCS (practical guidance from cardiology experts and breed health programs):

- Annual auscultation (listening for a murmur) from puppyhood; if a murmur is detected, refer for echocardiography. - Baseline echocardiographic screening by a board-certified cardiologist is often recommended for breeding candidates (many breeders obtain an echo at ~2 years, then repeat at intervals recommended by the cardiologist—commonly annually or every 1–2 years depending on findings). - Use echo reports (severity of mitral regurgitation, valve morphology, and regurgitant jet) to guide breeding decisions; many breed clubs set age thresholds and echo criteria for approval to breed.

• Why DNA testing is limited for MMVD: multiple genome-wide association and linkage studies have identified loci that contribute to risk, but no single variant explains the high breed prevalence; therefore, clinical screening remains the gold standard for MVD risk management [1,2].

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MRI screening for Chiari-like malformation and syringomyelia (CM/SM)

• CKCS are predisposed to CM/SM; MRI is required to diagnose and to grade syrinxes. The BVA/KC (UK) and other national schemes provide MRI protocols and scoring systems; many surgical or medical decisions are based on MRI findings.
• Typical recommendation: MRI at 12–24 months for breeding candidates (some schemes accept older ages for repeat screening); symptomatic dogs should be imaged earlier. Specific sequences and grading are critical—seek a radiologist/neurosurgeon experienced with CM/SM in CKCS.
• Cost and logistics: MRI requires general anesthesia, specialized sequences, and expert interpretation; expect higher costs than routine imaging ($1,500–$6,000 in many referral centers). Results guide breeding as well as clinical management.

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Practical breeding recommendations (breed-club–level and clinic-level actions)

• General principles for CKCS breeders:

- Test breeding stock for BCAN (EFS), FAM83H (CCDE), SOD1 (DM), and TUBB1 (macrothrombocytopenia) prior to use in the breeding program. - Avoid mating two carriers for autosomal recessive conditions (BCAN and FAM83H): carrier×carrier will produce ~25% affected puppies on average. - For SOD1, avoid producing A/A puppies: do not mate two A carriers (G/A) or an A/A with a G/A. Many programs recommend using at least one clear (G/G) parent or using carrier×clear matings while selecting for clear progeny. - For TUBB1 macrothrombocytopenia, because expression and clinical impact are often benign, the decision is more nuanced: document genotypes, avoid producing situations that complicate clinical care, and discuss openly with buyers about platelet findings. - Always combine DNA testing with clinical screening (echo for MMVD, MRI for CM/SM, ophthalmology where relevant). Neither DNA testing nor clinical screening alone is sufficient to manage breed health.

• For pet owners considering a CKCS puppy:

- Ask the breeder for genetic test results and clinical screening reports for both parents (echo reports and MRI/CM/SM scores where applicable). - If puppy is from a carrier pairing, the breeder should disclose carrier/affected status and outline plans for managing and/or monitoring health. - If you acquire a carrier or affected dog as a pet, work with your veterinarian to anticipate and manage condition-specific risks (e.g., neurology consult for EFS; platelet interpretation for surgery; neurologic monitoring for SOD1-positive dogs).

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What test results mean in everyday terms — owners vs breeders

• Pet owners:

- A “carrier” result for an autosomal recessive condition means your dog is healthy but can pass the variant to puppies; no disease is expected in the dog. - An “affected” genotype means the dog is at genetic risk or will develop disease (depending on condition), and appropriate clinical follow-up is required. - For SOD1, a positive genotype raises lifetime risk for DM but is not a diagnosis—watch for gradual hindlimb weakness and consult neurology if signs appear. - For macrothrombocytopenia, flag low platelet counts on the dog’s medical record so future veterinarians will interpret lab results correctly and take appropriate precautions for surgery.

• Breeders:

- Use genotypes to avoid producing affected puppies while maintaining genetic diversity. Do not simply cull all carriers without a considered plan; instead use managed matings (carrier × clear) and prioritize clear offspring. - Combine DNA results with clinical breeding criteria: cardiology (echo) and MRI results are essential for breeding decisions concerning MVD and CM/SM, respectively. - Be transparent with buyers: provide copies of genetic test reports and clinical screening records.

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Limitations and important caveats

• Negative DNA tests do not guarantee freedom from disease. For example, absence of known variants does not reduce MMVD risk to zero — MMVD is polygenic and clinically screened rather than DNA-screened at present.
• Penetrance and expressivity vary: some dogs with risk genotypes never show disease (notably SOD1), while others develop clinical signs. Environmental and additional genetic modifiers influence outcomes.
• Test quality varies between labs; use accredited/clinical-grade laboratories (e.g., UC Davis VGL, other university-based labs, OFA-registered results, and reputable commercial labs such as Embark) and request full genotype reports if you are using results for breeding decisions.
• Cost and access: comprehensive panels and specialist imaging can be expensive; plan financially if you intend to screen breeding stock. Some breed clubs provide subsidies or centralized schemes.

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Choosing a testing laboratory and interpreting results

• Recommended labs/registries to check for availability and reporting standards:

- UC Davis Veterinary Genetics Laboratory (VGL) — clinical-grade tests and consultations (vgl.ucdavis.edu) [9]. - OFA (Orthopedic Foundation for Animals) — maintains public registries including SOD1 results and cardiac databases; accepts test submissions and posts health databases (ofa.org) [5]. - Embark, Wisdom Panel, Animal Genetics — commercial test providers offering panels that include some of these Cavalierspecific variants; confirm which variants are covered before purchasing (embarkvet.com). - National/local breed health schemes (e.g., BVA/KC Chiari & SM scheme in the UK) for MRI screening protocols and scoring (bva.org.uk) [3].

• When you get a report:

- Ensure it specifies the exact variant tested, the genotype (e.g., BCAN: N/N, N/M, M/M), and interpretation (clear/carrier/affected). - For breeding, request echo and MRI reports (copy of the cardiologist’s echo report, DICOM images or radiologist’s MRI report) in addition to DNA reports. - If results are confusing, consult a veterinary geneticist, breeder mentor, or your specialty veterinarian for help interpreting how the genotype interacts with phenotype and breeding goals.

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Key Takeaways

• Several clinically important, breed-specific DNA tests are available for Cavaliers: BCAN (EFS), FAM83H (Curly Coat / Dry Eye), TUBB1 (macrothrombocytopenia), and SOD1 (degenerative myelopathy). Use tested, clinical-grade labs for results that will guide breeding and care.
• MMVD (mitral valve disease) in CKCS is polygenic and common; there is currently no single DNA test for MMVD—regular cardiac screening with auscultation and echocardiography remains essential.
• MRI is the diagnostic standard for CM/SM in CKCS; follow established MRI screening schemes (BVA/KC or local equivalents), and have imaging read by experienced neurologists/radiologists.
• For autosomal recessive conditions (BCAN, FAM83H), avoid carrier×carrier matings. For SOD1, avoid producing homozygous A/A pups; use mate selection strategies to reduce allele frequency while maintaining diversity.
• A positive genetic result is not always a forecast of immediate disease—penetrance varies. Combine genotype information with clinical screening, family history, and veterinary guidance when making health or breeding decisions.
• Pet owners of Cavaliers should request both genetic test results and clinical screening reports from breeders; breeders should be transparent and use tests responsibly to prevent affected puppies while preserving healthy genetic diversity.
• If in doubt, consult a board‑certified specialist (cardiologist, neurologist, ophthalmologist) and/or a veterinary geneticist to interpret results and to formulate care and breeding plans tailored to your dog.

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References and further reading

ACVIM Consensus Statement on MMVD (guidelines and breed implications), Journal of Veterinary Internal Medicine (2019).

Breed-specific studies and review articles on mitral valve disease in Cavalier King Charles Spaniels (see veterinary cardiology literature).

BVA/KC Chiari and Syringomyelia MRI screening scheme — guidance for imaging and scoring (www.bva.co.uk).

Awano T, et al. SOD1 mutation and canine degenerative myelopathy (original association paper, 2009).

OFA (Orthopedic Foundation for Animals) — genetic test registries and SOD1 resources (www.ofa.org).

UC Davis VGL — test pages for Episodic Falling (BCAN), review and test ordering (vgl.ucdavis.edu).

Veterinary genetics and hematology literature on TUBB1-associated macrothrombocytopenia in dogs; OFA platelet/hematology registries.

Published breed reports linking FAM83H-associated variants to curly coat / dry eye in CKCS (see breed-club health reports and VGL).

Commercial test providers (Embark, Wisdom Panel) — scope of panels and consumer pricing (embarkvet.com; wisdompanel.com).

(If you want, I can provide direct links to the specific test pages and the most up-to-date lab pricing in your country, or a sample breeder-health checklist you can give to puppy buyers.)