Finnish Lapphund Pompe Disease (GSD II): What Helsinki Research Shows

SamBoth parents of our Finnish Lapphund puppy had a “Pompe test.” Should that worry me?

Elena MarshIt is a reason to ask questions, not to panic. The disease traces back to a few Nordic dogs, and University of Helsinki scientists found its genetic cause in 2013.

SamIf it is that unusual, why do kennel clubs still list the test?

Elena MarshBecause it is recessive, a carrier can look healthy for life. A published DNA survey of Lapphunds shows why breeders still screen, and also what its numbers do not say.

SamIf my dog got sick, would the DNA result tell the vet what was wrong?

Elena MarshOnly partly. The research group behind the discovery notes that no early sign is specific to Pompe disease, so a genotype supports a vet’s work-up rather than replacing it.

Bottom line: Pompe disease (glycogen storage disease type II, GSD II) in the Finnish Lapphund is an autosomal recessive disorder caused by one known variant in the GAA gene, c.2237G>A (p.W746*), which a University of Helsinki study published in 2013 identified after four of seven puppies in a 2010 litter fell ill. Only dogs with two copies (P/P) develop the disease; N/P carriers stay healthy but can pass the variant on. In that study 5 of 95 Finnish Lapphunds were carriers, all from one pedigree: a 2013 snapshot, not a current breed-wide rate. The Royal Kennel Club lists the GSDII DNA test as Best Practice for the breed, and the American Kennel Club includes it among recommended tests. Affected dogs in the published reports showed regurgitation, weakness and panting from late puppyhood. A test result is breeding and risk information, not a diagnosis: if a young Lapphund is unwell, diagnosis belongs to your veterinarian, and no approved treatment for dogs has been identified.

From a Swedish case in 1970 to a Finnish litter in 2010

The canine disease was described decades before anyone could test for it. According to the OMIA entry for canine GSD II, “This canine disorder was first reported by Mostafa (1970), in a Swedish Lapland dog.” That dog had been diagnosed clinically with tonsillitis, a dilated oesophagus and myocarditis, after increasing difficulty swallowing, occasional vomiting, heavy mucus in the throat and poor growth. Its tissues told another story: a greatly enlarged heart and histochemical changes that “conformed to the classic form of Pompe’s disease.”

In the early 1980s H. C. Walvoort and colleagues in the Netherlands turned the condition into a research model. A 1982 biochemical study of one affected Lapland dog found glycogen “substantially elevated in heart and skeletal muscle but not in the liver.” A 1984 cell-fusion study showed that combining the dog’s cells with cells from healthy dogs or human patients did not restore the enzyme, pointing to a primary defect in acid α-glucosidase. By 1985 the group had shown recessive inheritance and called the dog disease a homologous model of infantile human Pompe disease. What the methods of the day could not do was name the mutation.

That came from Finland. In a Finnish Lapphund litter born in 2010, “Four out of seven puppies … were affected by slowly progressive muscle weakness and from frequent vomiting.” Blood could be collected from two of them. Lohi’s canine genetics group at the University of Helsinki, working with Dr Reuser at Erasmus MC in the Netherlands, sequenced GAA and found both puppies homozygous for c.2237G>A. The team then revisited a Swedish Lapphund born in 1979, diagnosed at four months by low enzyme activity in white blood cells and euthanised at fourteen months. A cell line grown from its tongue tissue had been stored in liquid nitrogen, and its DNA carried the same homozygous change. The paper calls the Finnish puppies the first correctly diagnosed cases in Finland and ends: “Forty years after the initial cases were reported our findings have finally enabled developing a genetic test to eradicate lethal Pompe disease from the Scandinavian dog breeds.”

SamSo a dog born in 1979 helped confirm the cause decades later?

Elena MarshYes. Its cells had been kept frozen, and the Helsinki team found the same homozygous GAA change in them, tying the old Swedish case to the new Finnish litter.

Where Pompe disease sits among the glycogen storage diseases

The short recap: glycogen storage diseases are inherited defects in the enzymes that build or break down glycogen, the storage form of glucose, so it accumulates in liver, muscle or both. Each type has its own gene; in dogs types Ia (G6PC1) and IIIa (AGL) are known, and in cats type IV (GBE1). Most types are faults in the main body of the cell. Type II is the exception: the missing enzyme works inside the lysosome, the cell’s recycling compartment, so Pompe disease is a lysosomal storage disease that hits heart, skeletal and smooth muscle far harder than the liver. A 1983 review by Walvoort listed natural GSD II in the dog, cattle and the quail, and a 2020 review of 42 animal models counted 15 naturally occurring ones, the dog among them, alongside 26 engineered mouse lines.

The Lapphund variant is a nonsense mutation: the change at position 2237 creates a premature stop at amino acid 746, so the enzyme loses its last 206 amino acids, about 22 percent of the protein. The Helsinki group found that the gene’s message is still made and an inactive protein is present, matching Walvoort’s earlier finding of enzyme protein without catalytic activity. The same p.W746* change has been reported in people, including four Italian infants and 9 of 40 late-onset patients whose second variant was c.-32-13T>G. The authors conclude that affected Lapphunds “mimic infantile-onset Pompe disease genetically, but also clinico-pathologically,” which makes them one of the few natural animal counterparts of the most severe human form.

Month by month: what the Helsinki case reports describe

The two Finnish puppies give the most detailed timeline published for the breed. Case 1 began regurgitating food at seven months, developed progressive weakness at eight, vomited mucus at twelve, and by thirteen months had persistent panting, voice changes and lethargy. Radiographs showed a dilated oesophagus (megaoesophagus) and an enlarged heart; ultrasound showed liver changes; blood work at eighteen months showed raised ALAT, urea and glucose and a low ALP. The dog was alive at about two years when the paper was written. Case 2 declined gradually from twelve months with weight loss, a poorer coat, loss of appetite and vomiting, had raised liver enzymes at fifteen and eighteen months, and was euthanised at nineteen months. Across both, the authors list “vomiting of mucous, panting, dyspnea, dysphagia, regurgitation and progressive muscle weakness.”

Walvoort’s 1985 summary in Veterinary Quarterly describes the same pattern: a picture “dominated by vomiting related to megaoesophagus, and progressive muscle weakness leading to exhaustion and death before two years of age,” with cardiac abnormalities. A pathology study of three related Lapland dogs found that the canine disease “closely parallels the infantile form of the human disease, except for the presence of oesophageal dilatation.” That dilated oesophagus is the dog-specific feature; human patients may struggle to swallow but do not develop it, and the Helsinki authors suggest, as a hypothesis, that posture may play a part.

Providers summarise the course slightly differently. LABOKLIN UK says signs start “at around seven month of age” and affected dogs “usually die around 1.5-2 years of age”; Embark gives onset “typically around 6 months.” These describe a handful of documented dogs, not a timetable for any individual.

SamLots of puppies throw up. How would I tell if it was something like this?

Elena MarshOften you could not at first. The Helsinki group’s owner sheet says no sign is disease-specific, so repeated regurgitation, weakness or panting in a young Lapphund needs a vet.

Five carriers in 95 dogs: how to read the 2013 survey

Once the variant was known, the Helsinki team screened healthy dogs of the three related Lapland breeds: “5% (5/95) of Finnish Lapphunds and 2% (2/99) of Lapponian Herders carry the mutation. The cohort of 34 Swedish Lapphunds did not contain any carriers.” Most Finnish Lapphunds and Lapponian Herders in the sample were unrelated at grandparent level. One detail in the pedigree figure matters more than the percentage: all five Finnish Lapphund carriers traced back to the same pedigree.

The team also tested 304 dogs of 21 other breeds, including Finnish Spitz, Samoyed and Keeshond, and found no carriers. With 9 to 21 dogs per breed, that shows the variant is not widespread elsewhere, not that any single breed is free of it. The authors read the pattern as a founder effect: all three Lapland breeds descend from Sámi herding dogs, and the Finnish Lapphund and Lapponian Herder were split by coat length only in the 1960s. A 2024 genomic study of century-old dog furs from northern Sweden adds that the Lapphund breeds arose from the local dog population and lost diversity under intense breeding, conditions in which one family’s variant can persist.

Three cautions follow. The 5-of-95 figure describes dogs sampled largely through the Helsinki DNA bank before 2013; it is not today’s carrier rate in the US, the UK or anywhere else, and it should not be turned into an expected number of affected puppies. The 2010 litter is a single litter. And nothing newer exists: a PubMed search covering 2014 to 2026 found no new canine Pompe case reports or carrier surveys, and we found no published breed-wide carrier figures since. The variant is in the breed, it was concentrated in one family when last measured, and its current frequency is unknown. The Lapponian Herder result points the other way: the paper “identified carriers from Lapponian Herders although no affected cases have been reported in this breed.” No reported case is not the same as no risk.

SamFive percent sounds high. Is one in twenty Lapphunds near me a carrier?

Elena MarshNo. Those 95 dogs came mostly from a Helsinki DNA bank before 2013, and every carrier traced to one family. No newer figure, and no US or UK figure, has been published.

N/N, N/P, P/P, and why the 1985 enzyme test was harder to read

Results are reported as two letters, one per gene copy. N/N means no copy carries the variant. N/P means one does: the dog is a carrier and is not expected to develop the disease. P/P means both do, and the dog is expected to be affected. Genomia’s test page puts it plainly: “the disease affects dogs with P/P (positive / positive) genotype only.”

Carrier status matters for breeding. LABOKLIN UK’s mating table shows that clear × carrier gives on average 50 percent clear and 50 percent carrier puppies with none affected, while carrier × carrier gives 25 percent clear, 50 percent carriers and 25 percent affected. Its advice: “Carriers should only be bred to clear dogs.” These are per-puppy probabilities, not a promise about a particular litter.

This used to be much harder. In 1985 Walvoort, Koster and Reuser tried to identify carriers in a family of twelve related Lapland dogs by measuring white-cell enzyme activity, and needed a specific antiserum to do it. Five dogs were classed as presumptive carriers, five as presumptive non-carriers, and “The results in two dogs were inconclusive.” A DNA test for a known variant has no such grey zone; the Royal Kennel Club calls a single-gene DNA test “an absolute test,” while noting that accuracy depends on the right sample and correct lab procedure.

“Absolute” covers only the variant tested. A clear result means the dog does not carry c.2237G>A; it says nothing about other causes of regurgitation, heart enlargement or weakness. The Finnish Lapphund Club of America makes the same general point on its health page: DNA tests assay specific mutations only, and a dog clear for one can still develop a clinically similar condition from another cause.

How the UK and US breed systems absorbed the test

By August 2013, according to a Kennel Club announcement reproduced by The Canine Chronicle, the Kennel Club had approved an official GSDII DNA testing scheme for the Finnish Lapphund after consulting the breed health coordinator. Results are added to the dog’s registration record, published in the Breed Records Supplement and on the Health Test Results Finder, and shown on offspring’s registration certificates.

Today the Royal Kennel Club’s Finnish Lapphund page has two tiers of pre-breeding screening. Good Practice, the minimum, is the prcd-PRA DNA test. Best Practice adds the “DNA test for glycogen storage disease (GSDII)” plus hip, elbow and eye schemes, for conditions that “might be less common or newly identified.” The breed is in Breed Watch Category 1 with no extra breed-specific breeding restrictions. The page notes that the Finnish Kennel Club recognised the breed as the Lappish Herder in 1945 and that it took its present name in 1993; the FCI lists it as the Finnish Lapponian Dog (Suomenlapinkoira), standard No. 189.

For a result to reach the Kennel Club record, LABOKLIN UK requires the dog’s microchip or tattoo number with its registered name or number on the report, and the owner’s signature on the order form’s declaration. For buyers in England, Lucy’s Law has since 6 April 2020 barred third-party sales of puppies under six months, so you deal with the breeder directly, and the GOV.UK breeding licence guidance requires a council licence for anyone breeding three or more litters in 12 months and selling puppies. Neither rule requires a GSDII test, so asking for the parents’ results is up to you.

In the US, the American Kennel Club breed page lists “Pompe Disease (GSD II) – DNA Test” among recommended health tests, alongside degenerative myelopathy, PRA-prcd, hip, elbow and patella evaluations and an eye examination. It ranked the breed 129th of 210 in popularity on 6 October 2026. The Finnish Lapphund Club of America links the Helsinki group’s Pompe information sheet from its health page.

SamBuying in the UK, can I check the parents’ Pompe results myself?

Elena MarshYes, on the Royal Kennel Club’s Health Test Results Finder. A result appears there when the lab report carried the microchip number and the owner signed the declaration.

Ordering the test: labs, turnaround and prices in pounds and dollars

Prices below were read on the providers’ pages on 6 October 2026 and may change.

UK — LABOKLIN UK. Test 8513 for GSDII costs £48.00 including VAT, with a stated turnaround of 2 to 3 weeks, on 0.5 to 1 ml of EDTA blood or cheek swabs (swabs and tubes free from the lab). The page identifies it as part of the official Kennel Club scheme for the breed. A Finnish Lapphund bundle (test 8249: degenerative myelopathy, prcd-PRA, GSDII and CMR) costs £138.00 including VAT and covers the DNA tests in both Kennel Club tiers in one order.

Ordered from abroad — Genomia. The Czech laboratory lists all three Lapland breeds for its GSDII test at 56.00 USD excluding VAT, usual turnaround 12 business days. We could not confirm transit times from the US or UK, so ask the lab about sample transport first.

US — Embark. Embark’s GSD II condition page names GAA, cites the 2013 Seppälä paper and lists all three breeds. It is part of the Breed + Health Dog DNA Test, $139 on sale against a regular $159, with free US shipping and sales tax not shown. That is a panel price, not a single Pompe test. The entry is labelled “Provisional,” so if the result will guide breeding, ask Embark what that label means for reporting.

A footnote: the 2013 paper disclosed that Genoscoper Oy, a company partly owned by Lohi, offered a commercial test for the three breeds. We could not find a current test page for it, so it is not listed as an option.

If a young Lapphund is unwell: the vet route and the insurance question

The Helsinki group’s information sheet, hosted by the Finnish Lapphund Club of America, says the disease “is difficult to diagnose by veterinarians because none of the symptoms are disease specific.” That is where a DNA result helps: it does not diagnose the dog, but it tells your vet whether this inherited cause is possible. The published cases indicate what a first work-up can include: chest radiographs (which showed the dilated oesophagus and enlarged heart in Case 1), abdominal ultrasound and blood work including liver enzymes. The sheet adds that the disease can also be confirmed by pathology after death, which matters for breeders trying to understand a litter loss.

Because heart, oesophagus and muscle are involved, referral may span specialties. In the US, VetSpecialists.com, the directory linked from the American College of Veterinary Internal Medicine, lists ACVIM board-certified specialists in cardiology, neurology and small animal internal medicine, and notes that “Your primary veterinarian may refer you to a veterinary specialist.” In the UK, ask your vet for a referral to a cardiology or internal medicine service. Bring the DNA report and the pedigree to the first appointment.

No approved treatment for dogs has been identified. Embark states, “There is no treatment except supportive care for the clinical signs the affected dog develops,” and the Helsinki sheet likewise says there is no treatment. Supportive care for regurgitation, breathing difficulty or heart failure is your veterinarian’s decision for the individual dog.

Insurance timing deserves thought before any signs appear. Embrace (US) covers hereditary and congenital conditions “when not pre-existing at the time of enrollment,” and Nationwide (US) states that “pre-existing conditions are not covered.” In the UK, Animal Friends treats a condition as pre-existing “if it was first noticed before your policy start date or within the waiting period,” and ManyPets sells a plan that covers “most pre-existing conditions (but not all of them).” None of these pages says whether a DNA result in a healthy dog counts as pre-existing.

SamWould a P/P result in a puppy with no symptoms count as pre-existing?

Elena MarshNone of the insurer pages we read says. Animal Friends counts anything first noticed before cover starts, so get your insurer’s position on genotype reports in writing.

What human medicine offers, and why it does not carry over to dogs

People with Pompe disease have an established treatment, enzyme replacement therapy (ERT), and its trials are often mentioned online alongside the dog disease. In a 2007 study in Neurology, 18 infants diagnosed at six months or younger received recombinant human acid α-glucosidase every other week; all survived to 18 months, and the risk of death was 99 percent lower than in untreated historical controls. In a 2010 randomised trial of 90 late-onset patients aged eight or older, treated patients walked 28.1 metres further in a six-minute test after 78 weeks.

None of this is evidence for dogs. The Helsinki paper calls ERT “currently the only effective treatment for human Pompe disease,” notes that it is not a cure, and suggests affected Lapphunds could be a model for testing gene therapy; we found no such canine studies published from 2014 onward. The practical message for the breed is prevention: test both parents before mating and pair any carrier only with a dog tested clear, so that no puppy from that mating can be P/P. That is what the UK scheme was built for in 2013, and the AKC’s recommended-test list points American breeders the same way.

Frequently asked questions

Q. Is Pompe disease common in Finnish Lapphunds?
There is no current figure. The only published survey, from 2013, found 5 carriers among 95 Finnish Lapphunds, all from one pedigree, and no newer data from the US, the UK or Finland has been published. Few affected dogs have been described, but that does not mean the variant is absent.

Q. My Lapphund is N/P. Will she get sick?
A carrier is not expected to develop Pompe disease, because it needs two copies of the variant. N/P matters for breeding: pair a carrier only with a dog tested N/N. If a carrier shows signs such as regurgitation or weakness, your veterinarian should look for other causes.

Q. Does an N/N result rule out heart or muscle disease?
No. It rules out this one GAA variant only. Diagnosing other causes of an enlarged heart or weakness is a job for your veterinarian and, if needed, a specialist.

Q. At what age do signs usually start?
In the published Finnish Lapphund cases, signs began between seven and twelve months, and providers describe onset around six to seven months. Two affected dogs in the reports were euthanised at 14 and 19 months, and one was alive at about two years when the paper was written. These are observations from a few dogs, not a fixed course.

Q. Can Pompe disease in dogs be treated?
No approved treatment for dogs has been identified; providers describe supportive care only. Enzyme replacement therapy is a human treatment and should not be assumed to apply to dogs.

Q. Does the same test work for Swedish Lapphunds and Lapponian Herders?
Yes. The c.2237G>A variant has been found in all three related Lapland breeds, and LABOKLIN, Genomia and Embark list all three. The 2013 survey found 2 carriers among 99 Lapponian Herders and none among 34 Swedish Lapphunds, which does not show the variant has disappeared from that breed.

References

• Seppälä EH, Reuser AJJ, Lohi H (2013). A Nonsense Mutation in the Acid α-Glucosidase Gene Causes Pompe Disease in Finnish and Swedish Lapphunds. PLoS ONE 8(2):e56825.
• Walvoort HC (1985). Glycogen storage disease type II in the Lapland dog. Veterinary Quarterly 7(3):187-190.
• Walvoort HC, Slee RG, Sluis KJ, Koster JF, Reuser AJJ (1984). Biochemical genetics of the Lapland dog model of glycogen storage disease type II (acid α-glucosidase deficiency). American Journal of Medical Genetics 19(3):589-598.
• Walvoort HC, Dormans JA, van den Ingh TS (1985). Comparative pathology of the canine model of glycogen storage disease type II (Pompe’s disease). Journal of Inherited Metabolic Disease 8(1):38-46.
• Walvoort HC, Slee RG, Koster JF (1982). Canine glycogen storage disease type II. A biochemical study of an acid alpha-glucosidase-deficient Lapland dog. Biochimica et Biophysica Acta 715(1):63-69.
• Walvoort HC, Koster JF, Reuser AJ (1985). Heterozygote detection in a family of Lapland dogs with a recessively inherited metabolic disease: canine glycogen storage disease type II. Research in Veterinary Science 38(2):174-178.
• Walvoort HC (1983). Glycogen storage diseases in animals and their potential value as models of human disease. Journal of Inherited Metabolic Disease 6(1):3-16.
• Mostafa IE (1970). A case of glycogenic cardiomegaly in a dog. Acta Veterinaria Scandinavica 11(2):197-208.
• Nicholas FW, Tammen I, Sydney Informatics Hub. OMIA:000419-9615: Glycogen storage disease II in Canis lupus familiaris (dog). Online Mendelian Inheritance in Animals (OMIA), University of Sydney. doi:10.25910/2AMR-PV70
• Kishnani PS, Corzo D, Nicolino M, et al. (2007). Recombinant human acid α-glucosidase: major clinical benefits in infantile-onset Pompe disease. Neurology 68(2):99-109.
• van der Ploeg AT, Clemens PR, Corzo D, et al. (2010). A randomized study of alglucosidase alfa in late-onset Pompe’s disease. New England Journal of Medicine 362(15):1396-1406.
• Almodóvar-Payá A, Villarreal-Salazar M, de Luna N, et al. (2020). Preclinical Research in Glycogen Storage Diseases: A Comprehensive Review of Current Animal Models. International Journal of Molecular Sciences 21(24):9621.
• Wang SZ, Yan Y, Widlund M, et al. (2024). Historic dog Furs Unravel the Origin and Artificial Selection of Modern Nordic Lapphund and Elkhound dog Breeds. Molecular Biology and Evolution 41(7):msae108.
• University of Helsinki (2013-02-18). Same genetic defect causes Pompe disease in both humans and dogs. ScienceDaily (press release).
• Canine Genetics Research Group (University of Helsinki / Folkhälsan). Pompe’s disease in Finnish Lapphunds (information sheet), hosted by the Finnish Lapphund Club of America.
• The Royal Kennel Club. Finnish Lapphund — Breeds A to Z (health section).
• The Canine Chronicle (2013-08-06). New DNA testing scheme for Finnish Lapphunds (Kennel Club announcement reproduced).
• American Kennel Club. Finnish Lapphund — Dog Breed Information.
• Fédération Cynologique Internationale. FCI-Standard N° 135 Svensk Lapphund (22.02.2012), N° 189 Suomenlapinkoira / Finnish Lapponian Dog (12.10.2016), N° 284 Lapinporokoira / Lapponian Herder (23.03.2026).
• Genomia s.r.o. Glycogenosis, GSDII (test page).
• Embark Veterinary. Pompe’s Disease (Glycogen Storage Disease Type II, GSD II) — health condition page.
• LABOKLIN (UK). Pompe’s Disease (Glycogen Storage Disease type II / GSDII), test number 8513; Finnish Lapphund DNA bundle, test number 8249 (accessed 2026-10-06).
• The Royal Kennel Club. Health Test Results Finder (accessed 2026-10-06).
• Department for Environment, Food & Rural Affairs. Dog breeding licence (England), GOV.UK guidance, published 4 November 2020 (accessed 2026-10-06).
• Department for Environment, Food & Rural Affairs. Lucy’s Law spells the beginning of the end for puppy farming, GOV.UK press release, 6 April 2020 (accessed 2026-10-06).

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.