Hemophilia A (F8) in Boxers: Auburn’s 2014 Family and the DNA Test Gap

SamOur Boxer puppy comes home next month, and the DNA sheet has a line for hemophilia A.

Elena MarshWorth reading slowly. The Boxer entry behind that line traces back to one family Auburn University described in 2014, a single pedigree’s mutation.

SamIt says “clear”. Can we tick bleeding disorders off the list and move on?

Elena MarshNot quite. Cornell’s coagulation laboratory writes that in dogs this disease arises through spontaneous mutation, so one clear genotype cannot cover all of F8.

SamThen what should we be asking the breeder, and what should we tell our vet?

Elena MarshDifferent questions. In a Tufts survey of 39 affected dogs, 34 were diagnosed before their first birthday, so puppyhood deserves as much attention as paperwork.

Bottom line: The only published Boxer cause of hemophilia A is a single-letter change in the factor VIII gene (F8), reported by Auburn University in 2014: c.1412C>G, which swaps proline for arginine at position 471 (P471R). The affected 11-week-old male had less than 1% of normal factor VIII activity; his dam and three sisters were carriers and a healthy brother was clear. Several labs now sell a “Boxer” hemophilia A test, but their pages do not all cite the same study, so ask which variant is read before you pay. A clear result covers that one variant only: hemophilia A also appears through new mutations in families with no history. The diagnosis is made by a veterinarian with an aPTT and a factor VIII activity assay, especially when a young Boxer bleeds at teething, after a vaccination or around a spay or neuter.

The American Kennel Club placed the Boxer No. 18 of 202 breeds in its 2025 registration ranking, and the Royal Kennel Club’s quarterly working-group figures record 2,427 Boxer registrations across 2024. US and UK details are separated below where they differ.

An 11-week-old male at Auburn and the relatives tested after him

The study is Christopherson, Bacek, King and Boudreaux in Veterinary Clinical Pathology (2014), from the Department of Pathobiology at Auburn University’s veterinary college in Alabama. Two patients reached the team with low factor VIII activity: an 11-week-old male Boxer and a 5-year-old male German Shepherd. The researchers amplified all 26 exons of F8 and sequenced them.

In the Boxer, exon 10 carried c.1412C>G. That one substitution changes the amino acid at position 471 from proline to arginine, inside the A2 domain of the factor VIII protein. In the family, the dam and three female littermates were heterozygous carriers, while an unaffected male littermate did not have the variant. A related Boxer with P471R was found later. The puppy’s factor VIII activity was below 1% of normal, which the authors compared with severe hemophilia A in people.

The German Shepherd in the same paper had a different change, c.1643G>A (C548Y), in exon 11. Each breed’s test is built on its own family.

A naming detail matters when you compare lab pages. The OMIA catalogue entry for canine haemophilia A now lists the Boxer variant under the current transcript as c.1469C>G p.(P490R). That is the same mutation renumbered for a signal-peptide offset, not a second Boxer variant. Only the abstract of the 2014 paper could be read for this article, so details such as where the family lived, how the puppy first bled and what happened to him are not reported here.

Why a healthy dam can still produce bleeding sons

SamThat dam looked fine. How does a healthy female pass on a bleeding disease?

Elena MarshF8 sits on the X chromosome. Cornell explains that a carrier female passes the faulty copy, on average, to half her sons and half her daughters, yet shows no signs.

A male Boxer has one X chromosome, inherited from his dam, so a single altered F8 copy leaves him with no working backup. A female has two X chromosomes; with one normal copy she usually clots well enough to look healthy. That is how the dam and three sisters could carry P471R unnoticed, while the affected puppy received the altered copy and his healthy brother the normal one.

The Cornell Comparative Coagulation Laboratory turns this into breeding guidance: “All daughters and dams of hemophilic males are obligate carriers of hemophilia and should not be used for breeding,” and “The full sisters and maternal half sisters of hemophilic males have a 50% chance of being carriers of hemophilia.” Put simply, once a male puppy is confirmed with hemophilia A, his mother is a carrier by definition, and every female from the same dam becomes a dog whose status needs checking before she is bred.

The sire’s side works differently. A male passes his X only to daughters, never to sons, so a clear stud cannot protect the boys in a litter from a carrier dam. Cornell adds that males confirmed clear “can safely be used for breeding without further propagation of the defect.” Female cases are not impossible, just unusual: in 2026 the University of Göttingen described a German Shepherd bitch with two copies of that breed’s variant (Brenig and Pach), and Gifu University in Japan reported a spayed mixed-breed female with 1.9% factor VIII.

Five sellers, one breed name, and an unanswered question about the variant

The Boxer has the widest commercial coverage of any F8 variant. Here is what each lab’s page said in October 2026.

• Embark has a condition page headed “F8 Exon 10, Boxer Variant”, marked “Provisional”, listing the Boxer as the only affected breed and citing Christopherson et al 2014.
• Orivet sells “Haemophilia A/Factor VIII Deficiency (Boxer Type)” and spells the target out: c.1412C>G in exon 10, P471R in the A2 domain, labelled Pathogenic.
• Wisdom Panel lists “Hemophilia A (Discovered in the Boxer)” with a C>G change at chrX 122,981,181 (CanFam3.1). That coordinate matches the position OMIA gives for the Auburn variant, but the page’s only reference is a 2013 congress abstract describing a stop-codon mutation, not the 2014 missense paper.
• LABOKLIN UK includes the Boxer in test 8689 alongside four other breeds, without naming which Boxer variant it genotypes.
• ANTAGENE (France) lists c.1412C>G for the Boxer, and AnimaLabs (Croatia) lists c.1469C>G, the renumbered form of the same change; Eurovet Gene names the F8 gene without stating a variant.

The pages do not let a buyer confirm that every seller reads the same change, and two of them say nothing either way. The safe move costs one email: before ordering, ask the lab whether its Boxer test reads c.1412C>G / P471R (also written c.1469C>G / P490R), and ask for that wording on the certificate. If you are comparing an older LABOKLIN UK result, note that test 8689 “replaces the old 8222D”.

Also note that Orivet’s Boxer profile also contains “Congenital Macrothrombocytopenia”, a platelet-size finding that has nothing to do with factor VIII; a dog flagged for one is not flagged for the other. For the separate Boxer spinal-cord test on the same panels, see our Boxer degenerative myelopathy (SOD1) article.

Heart, hips and DM fill the Boxer’s official lists; clotting never appears

SamOur breeder did every test the club asks for. Wouldn’t a bleeding test be on that list?

Elena MarshLists follow what owners report most. The Boxer Breed Council’s 2026 survey drew 1,066 replies; cancer and allergy led, and bleeding was not even a category.

In the US, the OFA’s CHIC program for Boxers requires a hip evaluation (OFA or PennHIP), autoimmune thyroiditis screening, an advanced cardiac exam that “must also include Holter”, and DNA results for DM and ARVC. The American Boxer Club’s recommended screening and its AKC Breeder of Merit requirements cover hip and elbow dysplasia, hypothyroidism, aortic valve disease, AS/SAS, Boxer cardiomyopathy and degenerative myelopathy. Hemophilia A appears in neither.

In the UK, the Royal Kennel Club Boxer page lists BVA/KC elbow, BVA/KC/ISDS eye and BVA/KC hip schemes as Best Practice, points to the breed club’s heart scheme, places the Boxer in Breed Watch Category 2, and says the RKC does not offer a breed-specific DNA package for the breed. The Boxer Breed Council’s Breed Health Survey 2026 covered registered, unregistered and rescue Boxers; a search of the report for haemophilia, bleeding, clotting and coagulation found nothing. A survey with no bleeding category cannot show the disease is absent, only that nobody has been counting.

The OFA database does hold one small window. Its Boxer statistics carry a HEMOPHILIA A row: 51 dogs tested, 50 normal or clear, one carrier, no affected entries. Read that as 51 owners choosing to submit, not as a breed frequency; the page does not say whether the entries are DNA results or factor assays, or which variant was read. Oddly, OFA’s own list of approved DNA labs shows a hemophilia A test only for the German Shepherd, so the registry and the lab matrix have not caught up with each other.

Bleeding with no family history: what new mutations mean for a clear Boxer

Cornell’s clinical page opens bluntly: “In dogs, as in other species, the disease arises as the result of spontaneous mutation.” The peer-reviewed record backs that up from several directions.

The largest clinical series is the Tufts University survey by Aslanian and colleagues (2014): 39 client-owned dogs with factor VIII activity of 20% or less, diagnosed between 1983 and 2013 and reported by veterinarians through specialist mailing lists and VIN. German Shepherds and their crosses (5) and Labradors and their crosses (4) were the largest groups, yet the authors judged the breed mix similar to the general dog population and wrote that the many breeds, crossbreds included, fit “de novo mutations with sporadic incidence patterns”. The same paper cites roughly 60 confirmed cases a year at Cornell’s laboratory, from unpublished data; that is one lab’s caseload, not a prevalence.

Individual reports show the same thing family by family. A University of Cambridge team found two affected males in a Weimaraner litter with no evidence of the disease three generations back (Dunning et al., 2009). LABOKLIN researchers traced a one-base deletion in a Border Collie litter to a mutation that most likely arose in the dam herself (Brockmann et al., 2023). And a University of Helsinki study of two unrelated Labrador families found an F8 deletion carried by all three affected males in the first family but no explanation at all in the other (Hytönen et al., 2023).

Cornell’s genetic work agrees. When Marjory Brooks’s group typed 78 dogs representing 14 breed variants of hemophilia A with six markers inside F8, the affected males of each breed variant had their own marker haplotype, and even two unrelated Jack Russell Terriers differed (Brooks et al., 2008). The authors called this clear allelic heterogeneity. For a Boxer owner the lesson is practical: P471R-clear means the Auburn variant is absent, not that F8 is guaranteed sound, and not that the dog cannot bleed for other reasons such as hemophilia B or an acquired problem.

Teeth, microchips, vaccines and the first neuter: how hemophilia A shows itself

The Tufts series is the best guide to timing. In 34 of the 39 dogs the diagnosis came before one year of age, and the events that most often triggered factor VIII testing were bleeding with teething, minor trauma, vaccination and elective surgery. Spontaneous bruising or a haematoma was the most common first sign (15 of 39). Across the course of the disease, bleeding was recorded under the skin in 26 dogs, into joints in 20, from the gums in 14 and at a surgical site in 10.

Microchipping deserves a mention because two recent reports began there: the Border Collie puppies developed acute haematomas after chip placement, and the Göttingen German Shepherd swelled badly after hers at three months. Bleeding can also be hidden. A 10-week-old Golden Retriever with severe pain on touch turned out to have bleeding inside the spinal canal (Lubbers et al., 2022), and in three young dogs described by Virginia Tech and UC Davis, two developed further bleeding after a spinal fluid sample was taken (Fowler et al., 2022). Embark’s Boxer page adds swollen joints, laboured breathing or a pendulous abdomen.

Ring your veterinarian promptly if a young Boxer, particularly a male, shows any of these:

• oozing from the mouth that outlasts the shedding of a puppy tooth;
• a lump that grows at an injection or microchip site over a day or two;
• lameness with a warm, puffy joint and no fall or knock you can identify;
• unexplained pain when picked up, or reluctance to move the neck or back;
• a scheduled neuter, spay or dental extraction when the dam’s history is unknown or a male relative bled.

Do not try to grade the risk from a single lab number. Tufts found no significant difference in spontaneous bleeding across factor VIII levels (P = 0.19) and concluded that residual activity “may not be useful for predicting severity of clinical signs, transfusion needs, or long-term prognosis.”

Confirming it: aPTT, factor VIII activity, and why carrier bitches are hard to call

SamIf our female puppy might be a carrier, can’t a blood test just tell us?

Elena MarshIt helps but may not settle it. A 1999 Cornell review explained that carrier and normal females overlap in factor levels, so ratios and pedigrees are used too.

For a bleeding dog the sequence is a screen, then a specific factor. Cornell’s page puts it this way: the aPTT “is abnormal in hemophiliacs”, but “a specific diagnosis of hemophilia A must be based on specific measurement of canine coagulation Factor VIII.” That second step is also what separates hemophilia A from hemophilia B, because the two look identical at the bedside and both prolong the aPTT. Our article on hemophilia B (F9) in the Rhodesian Ridgeback covers the factor IX side.

Carrier detection is harder. Cornell states that “coagulation assays may not always distinguish between carrier and clear females”, and that accuracy improves when factor VIII is set against von Willebrand factor as a ratio, though “it is still possible, however, for some carrier females to be misclassified.” The same overlap problem runs through Brooks’s 1999 review in the Journal of Heredity. Before causal mutations were known, Cornell used markers inside F8 instead: in a Golden Retriever family with mild disease, a marker allele that travelled with hemophilia let the team classify five suspect daughters (Brooks et al., 2005). For Boxers, where a family variant is known, a DNA result for a sister of an affected male is far more decisive than her factor level; for a bitch from an unexplained bleeding family, the pedigree and the ratio still matter.

US route. Your regular vet draws citrated plasma and ships it frozen to a coagulation laboratory such as Cornell’s, which runs both diagnostic factor VIII assays and carrier-detection testing for females; its program is confidential, with results released only to the submitter. Cornell’s fees are not published outside its online portal; ask your clinic.

UK route. A first-opinion practice can run the aPTT in-house or send it out; SRUC Veterinary Services in Scotland lists an APTT at £31 (VAT treatment not stated). A specific factor VIII assay is a send-out: LABOKLIN’s European laboratory offers one (service 597) on citrate plasma that must stay frozen until it reaches the lab, reporting on the day the sample arrives. For a UK dog that means frozen plasma travelling to a lab in Europe, so ask your vet to arrange the shipment. No UK pound price for a canine factor VIII assay was published at the time of writing.

Transfusions in the clinic, gene therapy in the research kennel

Bleeding episodes are managed by the veterinary team with blood products; 30 of the 35 treated dogs in the Tufts survey received transfusions. A Melbourne study comparing fresh-frozen plasma with cryoprecipitate in hemophilia A dogs found that cryoprecipitate raised factor VIII about as well with fewer reactions (Stokol and Parry, 1998). Treated dogs can form antibodies against the factor they receive: a Japanese Chin at Angell Animal Medical Center kept bleeding after dental work despite pre-operative product and turned out to have a factor VIII inhibitor (O’Kelley et al., 2009). Doses belong to your vet.

Dogs have also been central to research on human hemophilia A. According to the OMIA history notes, one research colony was founded at the University of North Carolina at Chapel Hill in 1947 from Irish Setters, and another at Queen’s University in Canada in 1980 from Miniature Schnauzers. The Chapel Hill dogs carry an F8 inversion of the same type as the intron 22 inversion common in severe human disease (Lozier et al., 2002), and a Queen’s team described a closely similar F8 defect in its own colony (Hough et al., 2002). In research dogs at Queen’s given a single liver-directed gene therapy dose, factor VIII expression persisted in the dogs that responded over a median 10.8 years of follow-up, and yearly bleeds fell from 3.9 to 0.3 (Batty et al., 2022).

Client-owned dogs have entered research too. A University of Pennsylvania study followed 12 companion dogs with severe hemophilia (11 with type A) for a median of 4.1 years after AAV gene therapy and reported 94% fewer bleeds (Doshi et al., 2024). The same report recorded two dogs whose factor VIII stayed at 1–5% dying of fatal bleeds, and the authors named “regulatory and financial hurdles” still to be cleared. A separate long-term study found clonal expansion of treated liver cells in five dogs and called for monitoring (Nguyen et al., 2021). This is research, not a treatment an owner can book for a Boxer, and no one should describe it as a cure for pet dogs.

Dollars, pounds, insurance wording and breeding rules

SamIs one hemophilia test cheaper than a panel that includes it?

Elena MarshDepends what else you need. Orivet listed the single Boxer-type test at $60 and its $139 Boxer profile adds DM and two other items; check the variant named first.

Prices were captured in October 2026; US figures exclude sales tax.

United States (USD). Orivet’s single Boxer-type hemophilia A test was $60.00; its Boxer Full Breed Profile, $139.00 with free shipping, bundles it with ARVC (marked research), congenital macrothrombocytopenia and degenerative myelopathy. Embark’s breed-and-health kits were on sale at $139 (regular $159), and Wisdom Panel Premium was $127.99 (regular $159.99, or four payments of $31.99).

United Kingdom (GBP). LABOKLIN UK test 8689 cost £48.00 including VAT, on EDTA blood (0.5–1 ml) or cheek swabs, with a stated turnaround of 2–3 weeks; there is no Boxer bundle in its UK catalogue. Wisdom Panel Premium UK was £144.99.

Insurance. Hemophilia A is lifelong, which shapes how pre-existing rules bite. Embrace lets a condition become eligible again if a pet is “symptom- and treatment-free for a year”, a route a dog with a permanent clotting defect is unlikely to use, and lists “DNA testing or cloning” under what is never covered. On the positive side, Embrace does cover hereditary and congenital conditions “when not pre-existing at the time of enrollment”. In the UK, Petplan says it will “cover conditions that haven’t shown symptoms before the start of your policy” but defines pre-existing as “a condition that you have noticed previously in your pet or that has been previously diagnosed by a vet”, and Animal Friends warns that a problem you noticed counts “even if you decided not to take them to the vet.” For a Boxer puppy, a gum bleed you noticed but never showed a vet before the policy started could become an exclusion; arrange cover before teething and the first neuter where you can.

Breeding law. England’s licensing rules (SI 2018/486, Schedule 6) say no dog may be kept for breeding if, “on the basis of its genotype, phenotype or state of health”, breeding could harm its health or that of its offspring. Hemophilia is not named, and whether a known carrier bitch falls under it is a matter of interpretation; Welsh and Scottish rules were not checked. In the US, rules vary by state; Florida’s § 828.29 is one example of a buyer remedy when a vet certifies a hereditary disorder within a year of sale.

Frequently asked questions

Q. How common is hemophilia A in Boxers?
No one has published a figure. The evidence is one Auburn family plus a related dog, and the OFA’s 51 voluntary entries (one carrier) are too few and too self-selected to estimate frequency in American or British Boxers.

Q. Do all the “Boxer type” DNA tests look for the same mutation?
The pages do not confirm it: Embark and Orivet cite the 2014 P471R paper, Wisdom Panel cites a 2013 stop-codon abstract, and LABOKLIN UK names no variant. Ask the lab for the variant name before ordering.

Q. Our male Boxer tested clear. Can he still have hemophilia A?
Yes, although it is unlikely to be the Auburn variant. New F8 mutations arise in families with no history, and hemophilia B or acquired clotting problems would not show on this test.

Q. Should a Boxer puppy have clotting tests before neutering?
Discuss it with your vet, especially for a male whose dam is untested or whose male relatives bled. An aPTT is a quick screen; a factor VIII assay is needed to confirm hemophilia A.

Q. Can a female Boxer develop hemophilia A?
It is rare. A carrier with one altered copy usually clots normally, though a few affected females have been reported in other breeds and mixed breeds.

Q. Is a DNA result a diagnosis?
No. It is risk information for breeding and planning. A veterinarian diagnoses hemophilia A with aPTT and factor VIII activity, and only a vet should decide on treatment.

References

• Christopherson PW, Bacek LM, King KB, Boudreaux MK (2014). Two novel missense mutations associated with hemophilia A in a family of Boxers, and a German Shepherd dog. Vet Clin Pathol 43(3):312-316.
• Aslanian ME, Sharp CR, Rozanski EA, de Laforcade AM, Rishniw M, Brooks MB (2014). Clinical outcome after diagnosis of hemophilia A in dogs. J Am Vet Med Assoc 245(6):677-683.
• Cornell University College of Veterinary Medicine, Animal Health Diagnostic Center, Comparative Coagulation Laboratory. Hemophilia A (clinical topic page). Accessed 2026-10-14.
• Brooks MB, MacNguyen R, Hall R, Gupta R, Booth JG (2008). Indirect carrier detection of canine haemophilia A using factor VIII microsatellite markers. Anim Genet 39(3):278-283.
• Dunning MD, Averis GF, Pattinson H, Targett M, Cade S, Herrtage ME (2009). Haemophilia A (factor VIII deficiency) in a litter of Weimaraners. J Small Anim Pract 50(7):357-359.
• Brockmann M, Mensing N, von Luckner J, Müller E, Kehl A (2023). Hemophilia A in a litter of Border Collies caused by a one base pair deletion in the F8 gene. Vet Clin Pathol 52(4):607-612.
• Batty P, Mo AM, Hurlbut D, Ishida J, Yates B, Brown C, Harpell L, Hough C, Pender A, Rimmer EK, Sardo Infirri S, Winterborn A, Fong S, Lillicrap D (2022). Long-term follow-up of liver-directed, adeno-associated vector-mediated gene therapy in the canine model of hemophilia A. Blood 140(25):2672-2683.
• Doshi BS, Samelson-Jones BJ, Nichols TC, Merricks EP, Siner JL, French RA, Lee BJ, Arruda VR, Callan MB (2024). AAV gene therapy in companion dogs with severe hemophilia: Real-world long-term data on immunogenicity, efficacy, and quality of life. Mol Ther Methods Clin Dev 32(1):101205.
• Online Mendelian Inheritance in Animals (OMIA). OMIA:000437-9615: Haemophilia A in Canis lupus familiaris (dog). University of Sydney. Accessed 2026-10-14.

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.