Muscular Dystrophy in the Cavalier King Charles Spaniel (DMD): Why a Clear Result Can Still Cover Only One of Two Variants

SamOur breeder sent an Embark report and said the Cavalier is clear of muscular dystrophy.

Elena MarshRead it closely rather than filing it. Embark’s own page titles that result “DMD, Cavalier King Charles Spaniel Variant 1” — and this breed has two published variants.

SamI did not know Cavaliers had muscular dystrophy at all. Is it common?

Elena MarshNobody can tell you how common. The reference laboratory that classifies these variants wrote in Genes in 2023 that most canine DMD mutations are isolated to a single case.

SamThen what is the point of paying for the test?

Elena MarshThe decision it changes is a breeding one. OMIA’s control advice is to test the female relatives of affected dogs — the allele travels invisibly through dams, not sires.

Bottom line: A clear commercial DNA result does not clear a Cavalier King Charles Spaniel of dystrophin-deficient muscular dystrophy. Two independent DMD mutations have been published in this one breed, and the mainstream consumer panels cover one of them — Embark labels its own result “Variant 1”. Only one test found for this article — Genomia’s, in the Czech Republic — names both variants in a single assay; LABOKLIN’s German brand Labogen reaches both, but only by buying two separate products. A DNA result is risk information for a breeding decision, never a diagnosis: the puppy that is stiff, drooling and struggling to eat at eight to ten weeks needs a serum creatine kinase measurement and a veterinarian, not a swab. Confirmation and all treatment decisions belong with your vet, and there is no approved treatment for canine dystrophinopathy.

The Cavalier King Charles Spaniel is the twelfth most popular breed in the United States on the American Kennel Club’s 2025 ranking, out of the 202 breeds counted in that year’s registration statistics — search-engine snippets commonly say 13, but the table on the page itself says 12. The AKC publishes ranks rather than counts, so for an absolute number you cross the Atlantic: the Royal Kennel Club registered 3,224 Cavaliers in 2025 (859, 780, 677 and 908 by quarter) inside a Toy Group total of 10,500 and an all-breed total of 161,901, down from 4,114 in 2016. Registrations are not a population count, but this is plainly a mainstream breed on both sides of the Atlantic.

Read Embark’s own label: “Variant 1”

Of the breeds with a published DMD variant, the Cavalier is by far the best served commercially. Embark’s muscular dystrophy page carries the sub-line “DMD, Cavalier King Charles Spaniel Variant 1”, gives the gene as DMD and the inheritance as X-linked recessive, shows breed cards for the Cavalier and the English Toy Spaniel, and states that “this mutation was first described in the Cavalier King Charles Spaniel”; the site banner offered Breed + Health at $139. Wisdom Panel heads the same condition “Muscular Dystrophy (Discovered in the Cavalier King Charles Spaniel)”, with gene “Dystrophin”, variant “G>T” and chromosome “X”. Mars’s breeder product, Optimal Selection, carries the same entry at $189.99 for Advanced and $129.99 for the standard panel.

That Optimal Selection list repays a second look: beside the Cavalier entry sit separate muscular dystrophy tests named for the Golden Retriever, Landseer, Norfolk Terrier, Labrador Retriever, Boston Terrier, Italian Greyhound and Staffordshire Bull Terrier. One product page thereby proves the central point — “muscular dystrophy” is not one test. The OMIA entry for Duchenne-type muscular dystrophy in the dog says it plainly: “all causative mutations occur within the dystrophin gene, although the molecular basis of the dystrophin mutation may be different between breeds.” OMIA catalogues 24 published canine DMD variants across 18 breeds as of 30 September 2026, from splice-site point mutations to multi-megabase inversions and retrotransposon insertions. A test validated in one breed says nothing about another.

Now the trap. Embark’s “Variant 1” is a commendably honest disclosure that the assay targets one lesion, and Wisdom Panel’s “G>T” matches the described G-to-T change at the intron 50 donor splice site — again a single lesion. LABOKLIN UK’s test 8068 costs £48.00 including VAT, describes the assay only as “PCR”, takes whole blood in EDTA (0.5 to 1 ml) or buccal swabs and quotes two to three weeks — but does not say which variant it covers, and that same product number also serves the American Staffordshire Terrier and the Landseer, where the disease sold under that name is autosomal recessive and a different gene, so the breed must always be named alongside the test. Antagene bundles it into an eight-disease Cavalier check-up at 168 EUR without naming a variant. Labogen, LABOKLIN’s German brand, sells the second lesion panel-only inside its LABOGenetics XXL profile under the abbreviation “MD2” — and that page does name it, and confirms the two-variant picture in one sentence: the variant is in “Exon 42 of the DMD (Duchenne muscular dystrophy) gene”, lies in “a secondary hotspot for muscular dystrophy”, and is inherited independently of “the variant in intron 50, which is also occurring in this breed”. So Labogen does reach both lesions — but only as two separate purchases. One single test commits to both: Genomia sells “DMD in Cavalier King Charles Spaniel (two mutations)” at $64.00 without VAT, naming them “c.7294+5G>T and c.6057_6063del”.

One breed, two mutations, three sets of coordinates

The first Cavalier lesion was published in PLoS ONE in 2010 by Walmsley and colleagues at the Royal Veterinary College as “a missense mutation in the 5′ donor splice site of exon 50”. OMIA has since re-described the identical lesion as NM_001003343.1:c.7294+5G>T, in the 5′ splice site of intron 51, with an experimentally confirmed splice defect, and corrected the genomic allele in a note dated 09/06/2025. Two descriptions, one consequence — and the consequence is the stable part: exon 50 is skipped, the reading frame breaks, and no dystrophin is made.

The second came from whole-genome sequencing of a single affected dog, published by Nghiem and colleagues in Mammalian Genome in 2017: a 7 base-pair deletion in exon 42 that shifts the reading frame, which those authors place “in a secondary DMD gene hotspot area distinct from” the first. Its coordinates have been written three ways. The paper published c.6051_6057delTCTCAAT; OMIA normalises it to c.6060_6066del with protein consequence p.(N2021Pfs*18), recording in a note dated 12/09/2026 that the published numbering had been based on a human transcript and that the correction was confirmed with Peter Nghiem himself; Genomia writes c.6057_6063del. None is wrong in context and none is canonical, so if a report quotes an HGVS string at you, ask which source the numbering came from.

SamThree different numbers for one deletion sounds like somebody made a mistake.

Elena MarshTwo people corrected it in public, which is the system working. OMIA records that the published numbering used a human transcript, and that its author confirmed the fix in 2026.

One more piece of bookkeeping: OMIA attaches a standing warning to its own variant table — “inclusion of a variant in this table does not automatically mean that it should be used for DNA testing” — and marks the AVCG pathogenicity classification of every canine DMD variant “Not currently evaluated”. An OMIA identifier is not an endorsement of a product built on it.

Why a London vet school keeps a colony of these dogs, and why they are not pedigree Cavaliers

The Cavalier is the best-tested DMD breed not because the disease is common in it, but because its mutation landed somewhere scientifically valuable. Walmsley and colleagues give the reason in their own words, writing about human patients: “70% of DMD patients harbour dystrophin gene deletions in a mutation rich area or ‘hot-spot’ in the central genomic region (exons 45–53)”, and the Cavalier exon 50 lesion sits inside it. That is why the same paper showed that antisense-mediated exon 51 skipping restored the reading frame and dystrophin protein in cultured myoblasts from an affected Cavalier, and why they proposed the breed as a cheaper, more tractable model than the large Golden Retriever dogs the field had been using: the phenotype was severe, but the dogs are small.

That work became the DE50-MD colony at the Royal Veterinary College in London, characterised by Hildyard and colleagues in 2022. Two facts about it belong in the same breath: it carries this breed’s exon 50 lesion, and it is not a colony of pedigree Cavaliers — the authors describe the line as descending from “an original founder Bichon-Frise cross Cavalier King Charles Spaniel female carrier”, outcrossed to Beagles. Kornegay’s 2017 review of the Golden Retriever model says the same of it: “GRMD is not a disease of pure-bred golden retrievers”. A severity statistic from a research colony describes colony dogs carrying a variant, not the breed in your living room.

None of this is treatment you can buy. Exon skipping and gene-transfer work in dogs is preclinical, and Kornegay’s review is explicit that the human standard of care remains a corticosteroid with “only palliative benefits”. There is no approved treatment for canine dystrophinopathy; management is supportive and your veterinarian’s to direct.

Creatine kinase in five figures: the test that finds a sick puppy

The DNA test and the sick puppy are two different problems. OMIA puts onset at “8 to 10 weeks of age”, with a shuffling or bunny-hopping gait, inability to open the jaw fully, difficulty eating, a thickened tongue base, heavy salivation, front paws turned outward, stifles and hocks drawn inward, and wasting of the temporal and trunk muscles. Cardiac involvement comes later — OMIA places the ventricular lesions “usually after 6 months of age” — so this is not purely orthopaedic.

What finds it at the first “clumsy puppy” appointment is serum creatine kinase, and the published figures in this breed are extraordinary. In the three affected Cavaliers of the 2010 series, CK was 33,695 U/L, 64,918 U/L and 58,508 U/L against a reference interval of 61 to 394 U/L — two orders of magnitude above normal, from a blood draw any general practice can send out. Dysphagia and macroglossia were noted as young as two months, and several colony dogs were later euthanised because of the swallowing difficulty. OMIA adds that CK elevation of up to 300 times normal begins in the first week of life and is worsened by exercise.

SamSixty thousand units. Would my own vet even believe a number like that?

Elena MarshThey will have seen it in dystrophinopathy. OMIA records creatine kinase running up to 300 times normal from the first week of life, and exercise pushes it higher still.

Confirmation in that series did not come from a swab. It came from open muscle biopsy — cranial tibial, vastus lateralis and triceps — with dystrophin immunohistochemistry against the rod and carboxy domains plus a Western immunoblot showing complete absence of the protein. That remains the diagnostic that works in any breed, including breeds with no known variant: OMIA states that where a mutation has not been reported, affected dogs “can be tentatively diagnosed by immunohistochemical tests for the presence or absence of dystrophin protein in skeletal muscle biopsy”, a pathway reviewed by Shelton and Engvall (2005).

One correction to a common assumption. Carrier females are usually clinically normal but not reliably so: because X-inactivation is random, OMIA records that carriers “can occasionally present with limb weakness and highly elevated serum creatine kinase, or show changes on electromyography or biopsy”, and in the Pembroke Welsh Corgi line the original authors reported mild myopathy in carriers too. This is X-linked recessive inheritance, not autosomal: a carrier dam bred to a normal sire gives, on average, half affected sons and half carrier daughters, and no affected daughters. The familiar clear/carrier/affected square does not apply, because the male has one X and nothing to compensate with.

The signs arrive before the policy can: the hardest condition in this breed to insure

This is the part with money in it. Every United States insurer whose wording could be read for this article defines a pre-existing condition as something the pet showed signs of before the waiting period ended. Now the timeline: signs at eight to ten weeks by OMIA’s account, dysphagia at two months in the published case series, one to three months on Embark’s page, and “as young as six weeks to three months” according to the breed-health website cavalierhealth.org, a secondary source. A puppy drooling, struggling to eat and stiff-gaited at ten weeks has therefore already shown signs before any policy a new owner could realistically have bought was in force. For that dog, this condition is effectively uninsurable.

SamSo if my puppy is already stiff at ten weeks, no policy is going to help me.

Elena MarshThat is the honest reading of the wording. Embrace counts anything you or your vet noticed before the waiting period ends as pre-existing, even if the dog was never seen for it.

The specifics come from the carriers’ own pages. Nationwide files congenital and hereditary problems under “what’s not covered”, with congenital coverage “available on select plans providing the condition is not visible or has not developed to the point where signs or symptoms are apparent”, limited hereditary coverage confined to its Major Medical plan, and its covered-benefits page confirming the Congenital and Hereditary element is an optional rider. Embrace covers hereditary and congenital conditions “when not pre-existing at the time of enrollment”, then defines pre-existing as “any injury, illness, or irregularity noted by you or your vet before your pet’s waiting period is over, even if your pet never went to see the vet for it” — the clause that closes the door, because noticing a clumsy puppy is enough. Lemonade, available in 43 states plus the District of Columbia, covers hereditary conditions in its base policy with waiting periods of 14 days for illness and 30 for orthopedic conditions, and states that “anything your pet has shown signs of before the waiting periods are up is considered a pre-existing condition”.

The commercial conclusion is arithmetic rather than salesmanship. Nobody insures this after the fact, so the whole workup lands on the owner: a CK panel, a $182 muscle profile, then a $425 dystrophy panel or a $316 immunoblot, plus a specialist consultation. Screening the dam before a litter exists costs $64 at Genomia for both published variants, or £48 at LABOKLIN UK for a test that does not state which variant it covers — money well spent one generation earlier than most people think about it.

What happens at La Jolla when DNA cannot answer the question

If a dog has a five-figure CK and a clear result on a single-variant panel, the question is no longer genetic but histological — and the United States has a named international reference centre for it: the Comparative Neuromuscular Laboratory at the University of California San Diego, directed by G. Diane Shelton and established in 1990. Its fee schedule, revised 01/01/2026, is public, so this is the rare part of the pathway you can budget exactly.

The sequence matters as much as the prices. Test 900, the complete muscle profile on a first muscle, is $182.00, each additional muscle or nerve $96.00, turnaround five to seven working days. The dystrophy work sits behind it: test 907.1, an expanded immunohistochemistry panel covering dystrophin, the sarcoglycans, laminin alpha-2, dysferlin, the dystroglycans and more, is $425.00, and the dystrophy immunoblot, 907.2, is $316.00, both at 14 to 21 working days. The laboratory gates them explicitly: “for tests 907.1 through 907.3 the Complete Muscle Profile needs to be requested first to confirm a histologic diagnosis of either a form of muscular dystrophy … prior to requesting the additional testing.” So the realistic figure is $182 and then $425, not $425 alone. A consultation is $190.00; DNA purification and storage, at $104.00, is the only DNA line on the schedule — which tells you this is a diagnostic reference centre, not a DMD test vendor.

Read the logistics before the biopsy is booked. The laboratory asks for an open biopsy of roughly 0.5 by 0.5 by 1.0 cm from “an affected but not end-stage muscle”, wrapped in saline-dampened gauze and chilled, received within 24 to 48 hours, with a second piece in 10% neutral buffered formalin; shipping is “FedEx/UPS Red Label only” with the instruction “do not use USPS” in its own capitals, and nothing should go out on a Friday. Arrange a submission through the laboratory’s web form or by telephone on (858) 534-1537.

Getting there runs through a specialist, and the right board is ACVIM Neurology. The directory is not on the college’s own domain: it is vetspecialists.com, created by the American College of Veterinary Internal Medicine and searchable by specialty, animal type and state, ZIP code or country. Referral is the norm rather than a legal requirement; the college’s guidance for animal owners reads, “Ideally, this is a decision you will make with your primary care veterinarian.” Some referral hospitals insist on a letter, so check before you drive.

Every official scheme on both sides of the Atlantic leaves this one out

The sharpest observation here is institutional, not statistical. In the United States, the OFA’s CHIC requirements for this breed are hip evaluation, an ACVO eye examination, patellar luxation and a cardiac evaluation — no DNA test at all — and muscular dystrophy appears in neither those requirements nor the national breed club’s scheme. In the United Kingdom the point is sharper still.

SamSurely a kennel club would require a test if this really mattered.

Elena MarshThey already require two other DNA tests in this breed. The Royal Kennel Club’s Good Practice list names curly coat with dry eye, episodic falling and the heart scheme — not this.

Note first that older sources are stale: the Assured Breeder Scheme URL now returns a 404, the Kennel Club trades as the Royal Kennel Club, and breed-specific scheme lists have been replaced by the Royal Kennel Club Health Standard, split into Good Practice and Best Practice. On the Cavalier breed page, Good Practice — the minimum the RKC “strongly recommend that breeders … conduct … before breeding” — is a DNA test for curly coat and dry eye, a DNA test for episodic falling, and heart screening for mitral valve disease under the Kennel Club scheme supported by the Veterinary Cardiovascular Society; Best Practice adds the BVA/KC/ISDS eye scheme. Muscular dystrophy is absent from the whole page. So the institutions governing this breed have already accepted that a DNA test can be required before breeding. They simply have not added this one.

On regulation, the United States has no federal genetic-testing mandate for dog breeding, and that is verifiable. The APHIS technical note “Q&A: Activities with Dogs Requiring a USDA License/Registration” defines who needs a licence — Class A breeder, Class B dealer or broker, Class C exhibitor — and the exemptions, including “maintaining a total of four or fewer breeding female dogs and selling (wholesale or retail) only the offspring of these dogs … for pets or exhibition”. The words “genetic” and “DNA” appear nowhere in it: the Animal Welfare Act and its regulations govern housing, husbandry, veterinary care, transport and recordkeeping, not heritable-disease screening. An APHIS dog-welfare rulemaking is open with comments extended to 20 April 2026, and whether it touches genetic screening is unknown. Nor can this article tell you that no individual state requires testing — all fifty statutes were not audited, so treat “no federal mandate” as the verified claim and check your own state.

What to actually buy, and who to test first

Begin with the honest frequency answer, because it shapes everything: no population frequency has been published for either Cavalier variant. The first was described in one family of Cavaliers in 2010, the second in a single dog in 2017, and Shelton and colleagues (2023) note that most canine DMD mutations are isolated to a single case. The only population-level screen in canine DMD, Broeckx and colleagues (2013), genotyped 476 dogs in Belgium, the Netherlands and Germany and found that the mutant allele “could not be identified in our population” — but it tested only the Golden Retriever allele. The breed-health website cavalierhealth.org mentions a UK study of 96 female Cavaliers in which no carriers were identified; that underlying study could not be located, so read it as a breed-community report rather than a published frequency. Any percentage quoted for this breed is a fabrication.

Which reframes the product: this is not a screening test for the general Cavalier-owning public. OMIA’s control recommendation is narrow — “female relatives of affected dogs should be tested to identify carriers. Breeding of affected or carrier animals should be avoided.” For an X-linked condition that resolves cleanly: you need not remove a carrier dam from a shrinking gene pool, you need to know she is a carrier so that you never produce affected sons from her.

If you do test, the comparison is short. Genomia at $64.00 without VAT is the only single test found that explicitly covers both published variants and names them (Labogen covers both too, but only across two separate products); LABOKLIN UK at £48.00 including VAT tests a swab or EDTA blood sample by PCR in two to three weeks without stating which variants; Embark at $139 and Optimal Selection Advanced at $189.99 include the Cavalier variant inside a large panel, labelled “Variant 1” by Embark. Prices and coverage were read on 30 September 2026 and do change; confirm before ordering. Two familiar names do not carry it: Orivet’s Cavalier Full Breed Profile at $139.00 covers eight conditions from airway distress syndrome to xanthine urolithiasis with no muscular dystrophy — notable because Orivet does sell a Pembroke Welsh Corgi DMD test, so this is a catalogue decision rather than a technical limit — and Animal Genetics lists two muscular dystrophy tests at $45.00 each — one for the Golden Retriever type and one for the Landseer — and neither is the Cavalier’s, nor does either appear in its $120.00 Cavalier panel. Treat UC Davis and Paw Print Genetics as unknown rather than absent: neither catalogue could be read.

And whatever the report says, it is one locus of one gene. A clear result on one variant does not clear the dog, and a clear result on both does not clear it of the other canine muscular dystrophies, which involve different genes and mostly autosomal inheritance. If your Cavalier puppy is bunny-hopping, cannot open its jaw properly, drools, struggles to swallow or is losing muscle over the skull and trunk, that is a same-week veterinary appointment with a creatine kinase on it — not a swab and a two-week wait.

Frequently asked questions

Q. My Embark report says clear for muscular dystrophy. Is my Cavalier clear?
Clear for the variant Embark tests, which its own page names “Variant 1”. Two DMD variants have been published in this breed — the exon 50 splice lesion from 2010 and the exon 42 seven base-pair deletion from 2017 — and of the products checked here, only Genomia’s single test states that it covers both (Labogen reaches both only by ordering two separate tests). A single-locus clear result is useful information, not a clean bill of health, and not a diagnosis either way. If you are buying a puppy, ask which variants were tested, on which dog, and to see the report.

Q. How common is this in Cavalier King Charles Spaniels?
Nobody knows, and no honest source will give you a percentage. Neither variant has a published population frequency: one was found in a single family, the other in a single dog. The only population screen ever run for a canine DMD variant tested the Golden Retriever allele in 476 European dogs and did not find it, which says nothing about this breed. A breed-health website reports a UK study of 96 female Cavaliers with no carriers identified, but it could not be verified at source.

Q. Can a carrier female be affected herself?
Usually not, but it is not guaranteed. Because X-inactivation is random, OMIA records that carriers can occasionally show limb weakness and highly elevated creatine kinase, or changes on electromyography or biopsy, and in the Pembroke Welsh Corgi line the original authors reported mild myopathy in carriers. If a carrier dam looks weak or exercise-intolerant, see your vet.

Q. My vet found a creatine kinase over 30,000. What does that mean?
Severe ongoing muscle damage, and it needs a veterinary neurologist rather than an internet answer. In the three affected Cavaliers of the 2010 series CK was 33,695, 64,918 and 58,508 U/L against a reference interval of 61 to 394. High CK is not specific to dystrophin deficiency, which is why the pathway continues to a muscle biopsy with dystrophin immunohistochemistry.

Q. Will pet insurance pay for this?
For a dog that already has signs, almost certainly not. Every US insurer read for this article treats anything noticed before the waiting period ends as pre-existing, and Embrace says so even when the dog was never taken in for it. Since signs in this breed start between roughly six weeks and three months, they usually pre-date any policy a new owner could have bought. Read the hereditary wording before you sign — with Nationwide it is an optional rider.

Q. Is exon skipping a treatment I can ask for?
No. Exon 51 skipping restored the reading frame and dystrophin protein in cultured cells from an affected Cavalier, and related work continues in research colonies such as the DE50-MD line at the Royal Veterinary College, but it is preclinical research. There is no approved treatment for canine dystrophinopathy; care is supportive and directed by your veterinarian.

References

• Walmsley GL, Arechavala-Gomeza V, Fernandez-Fuente M, Burke MM, Nagel N, Holder A, Stanley R, Chandler K, Marks SL, Muntoni F, Shelton GD, Piercy RJ (2010). “A Duchenne muscular dystrophy gene hot spot mutation in dystrophin-deficient Cavalier King Charles Spaniels is amenable to exon 51 skipping.” PLoS ONE 5(1):e8647.
• Nghiem PP, Bello L, Balog-Alvarez C, Mata López S, Bettis A, Barnett H, Hernandez B, Schatzberg SJ, Piercy RJ, Kornegay JN (2017). “Whole genome sequencing reveals a 7 base-pair deletion in DMD exon 42 in a dog with muscular dystrophy.” Mammalian Genome 28(3-4):106-113.
• Hildyard JCW, Riddell DO, Harron RCM, Rawson F, Foster EMA, Massey C, Taylor-Brown F, Wells DJ, Piercy RJ (2022). “The skeletal muscle phenotype of the DE50-MD dog model of Duchenne muscular dystrophy.” Wellcome Open Research 7:238.
• Shelton GD, Minor KM, Friedenberg SG, Cullen JN, Guo LT, Mickelson JR (2023). “Current Classification of Canine Muscular Dystrophies and Identification of New Variants.” Genes 14(8):1557.
• Shelton GD, Engvall E (2005). “Canine and feline models of human inherited muscle diseases.” Neuromuscular Disorders 15(2):127-138.
• Kornegay JN (2017). “The golden retriever model of Duchenne muscular dystrophy.” Skeletal Muscle 7:9.
• Broeckx BJG, Coopman F, Verhoeven GEC, Van Haeringen W, van de Goor L, Bosmans T, Gielen I, Saunders JH, et al. (2013). “The Prevalence of Nine Genetic Disorders in a Dog Population from Belgium, the Netherlands and Germany.” PLoS ONE 8(9):e74811.
• Smith BF, Yue Y, Woods PR, Kornegay JN, Shin JH, Williams RR, Duan D (2011). “An intronic LINE-1 element insertion in the dystrophin gene aborts dystrophin expression and results in Duchenne-like muscular dystrophy in the corgi breed.” Laboratory Investigation 91(2):216-231.
• OMIA (Online Mendelian Inheritance in Animals). “OMIA:001081-9615: Muscular dystrophy, Duchenne type in Canis lupus familiaris (dog).” University of Sydney.
• OMIA variant 367: the Cavalier King Charles Spaniel exon 50 splice variant.
• OMIA variant 562: the Cavalier King Charles Spaniel exon 42 seven base-pair deletion.
• Comparative Neuromuscular Laboratory (Director: G. Diane Shelton, DVM, PhD, DACVIM), Department of Pathology, School of Medicine, University of California San Diego.
• Comparative Neuromuscular Laboratory, UC San Diego. Diagnostic service fee schedule and submission instructions, “Revised 01/01/2026”.
• American College of Veterinary Internal Medicine. “Find a Specialist” directory (vetspecialists.com).
• American College of Veterinary Internal Medicine. “Animal Owners”: guidance on referral to a specialist.
• Embark Veterinary. “Muscular Dystrophy (DMD, Cavalier King Charles Spaniel Variant 1).”
• Wisdom Panel. “Muscular Dystrophy (Discovered in the Cavalier King Charles Spaniel).”
• Optimal Selection. “Optimal Selection Advanced – Canine” test list.
• LABOKLIN UK. “Muscular Dystrophy (MD)”, genetic test 8068.
• Genomia s.r.o. “Testing of dogs: DMD in Cavalier King Charles Spaniel (two mutations).”
• Labogen / LABOKLIN. “Muscular dystrophy (Duchenne type) – Cavalier King Charles Spaniel.”
• Antagene. “Cavalier King Charles Spaniel – Genetic Check-Up.”
• Orivet. “Cavalier King Charles Spaniel – Full Breed Profile.”
• Animal Genetics. Canine DNA test catalogue.
• American Kennel Club. “The Most Popular Dog Breeds of 2025.”
• Royal Kennel Club. “Breed registration statistics”: quarterly Toy Group statistics and ten-year comparative tables.
• Royal Kennel Club. “The Royal Kennel Club Health Standard.”
• Royal Kennel Club. “Cavalier King Charles Spaniel” breed page: Good Practice and Best Practice health tests.
• Nationwide Pet Insurance. “What’s not covered.”
• Embrace Pet Insurance. “What’s covered”, including the definition of a pre-existing condition.
• Lemonade. “Pet insurance”: coverage, waiting periods and pre-existing conditions.
• USDA APHIS Technical Note. “Q&A: Activities with Dogs Requiring a USDA License/Registration” (November 2018).
• CavalierHealth.org. “Muscular Dystrophy” (breed-health website; secondary source).

About the author

Elena Marsh

Editor & writer (not a veterinarian)

A writer with a molecular-biology background and a lifelong dog and cat owner. Not a veterinarian — she translates peer-reviewed genetics research and primary data into plain language, always as information rather than diagnosis.