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Portuguese Water Dog

Portuguese Water Dog
Photo: Silke Hollje-Schumacher / CC BY-SA 3.0 · Wikimedia

42 Portuguese Water Dogs in the atlas. Every number on this page has a source.

Population-genetic snapshot of Portuguese Water Dogs in the Sniff Atlas, source-graded Mendelian carrier frequencies from Donner 2023, and nutrition guidance tied to the genetic findings above.

Also known as Cao de agua Algarvio, Cao de agua Portugues, Cão de Agua, and Portie.

See in the atlas → From CanVAS
The plain version

Portuguese Water Dogs have a surprisingly wide variety of genetic backgrounds compared to many other breeds, which is a good sign for their overall health. They are known for their curly coats and energetic personality, making them great companions for active families. One health note is that their gene pool includes a risk for certain back issues, so it’s a good idea to talk with your vet or consider genetic testing to understand this better. Overall, they’re a lively and unique breed with a strong genetic foundation.

What the atlas says about Portuguese Water Dog

In the atlas, the Portuguese Water Dog clusters consistently as Portuguese Water Dog (100% of the 42 dogs here). Genetic diversity is high (mean heterozygosity 0.3562), reflecting either a mixed-breed cluster or breeds with broad genetic backgrounds. At the trait loci, KRT71 runs lower than average (32% here vs 91%); FGF4_retrogene_CFA12 runs lower than average (40% here vs 80%).

Ranks 91 of 107 on the bottleneck severity scale, in the upper quartile of genetic diversity. Mean heterozygosity is 0.356, notably high, indicates broad genetic background. Low breed predictability score (0.26), individual dogs of this breed vary widely in genetics, suggesting active substructure or sub-population diversity.

Genetic dimensions · CanVAS atlas

What the genome says about Portuguese Water Dog

Computed from the 18,477 research dogs in the Atlas.

Dogs in the Atlas
42Founders
23 from Cairns, 10 from Spatola, 9 from Hayward2016
Genetic diversity
0.36Diverse
Mean heterozygosity across the breed. Ranks 91st most genetically tight of 107 ranked breeds.
What does genetic diversity mean?

How varied a breed's gene pool is — the share of gene spots where a typical dog of the breed carries two different versions rather than two identical ones.

How to read it: Higher = more diverse. Among well-sampled breeds it ranges roughly 0.22 (least diverse) to 0.33 (most diverse).

Diversity is a strength, not a verdict on any individual dog. Lower diversity means it's worth paying attention to recessive-risk testing — not that a dog is doomed.

Cluster structure
Splits into two genetic sub-populations
Intra-breed RMS distance: 31.47 · likely working/show-line, regional, or kennel lineage split.
What does within-breed variation mean?

How much individual dogs within the breed differ from each other genetically.

How to read it: Higher = more internal variety among individuals of the breed.

Sensitive to how many dogs of the breed we've sampled.

Related breeds
Gave rise to
In the Other group
Explore the full lineage map →
VBO foundation stock (breeding records) · AKC breed group
Relatedness is documented lineage + kennel family. Genetic-ancestry distance measures diversity, not kinship, so it isn't used here.
How long they live
13years (life expectancy)
95% CI 11.5–14.9 · VetCompass, McMillan 2024, n=179. source
What does typical lifespan mean?

The median age dogs of the breed tend to reach.

How to read it: Higher = longer-lived. Compare to longevity-for-size to see whether it's just a size effect.

Drawn from population lifespan records; individual dogs vary widely with care, genetics, and luck.

Trait genetics
Allele frequencies at named morphology loci

Frequency of the alternate allele in this breed at each locus's representative SNP.

Body size
IGF142%
HMGA271%
SMAD234%
LCORL88%
STC279%
ADAMTS1789%
Leg length
FGF4·CFA1860%
FGF4·CFA1240%
Coat
RSPO275%
FGF579%
KRT7132%
MC1R79%
Ear set
MSRB378%
Skull shape
BMP365%
SMOC266%
n = 42 dogs · moderate confidence · CanVAS (Brundage 2026) · Sniff Atlas
Names & origins

Other names

The Portuguese Water Dog is also recorded as Cao de agua Algarvio, Cao de agua Portugues, Cão de Agua, Portie, Portugese water dog, PWD, and Water Dog.

Identified as Portuguese Water Dog (VBO:0201077) in the Vertebrate Breed Ontology (Mullen et al. 2025, CC-BY 4.0) · registry IDs FCI 37 · iDog 194 · VeNom 15118.

What you see when you look at a Portuguese Water Dog

What does the genome say about how a Portuguese Water Dog looks?

Portuguese Water Dogs look the way they do because of a small set of fixed and near-fixed morphology genes that, taken together, define the visible breed. Each translation below pairs the gene with the trait an owner actually sees, the breed's allele frequency at that locus, and a one-clause causal phrase.

Where the breed-defining genes act, mapped on a generic dog-body key — and how fixed each marker is in the Portuguese Water Dog. The figure is the most-settled marker we read in that region; the full per-locus panel is below. (The silhouette is a shared anatomical guide, not this breed's outline.)

Body sizeADAMTS17 · 89%Skull shapeSMOC2 · 66%EarsMSRB3 · 78%Leg lengthFGF4 CFA18 · 60%Coat & colorFGF5 · 79%
CanVAS trait-locus panel (Brundage 2026)
15 morphology markers read across 5 regions. Allele frequency = how fixed a marker is in this breed, not whether your dog carries it.

Size and build

IGF1 sits at 42% for the small-body allele. IGF1 is the gene that sets dog body size from Chihuahua to Great Dane. Intermediate frequencies typically keep a breed in the mid-sized range rather than tipping toward the larger working forms.

IGF1what this gene does

IGF1 is a gene that plays a key role in determining a dog's body size. It influences how much a dog grows, affecting overall stature.

For your dog: Knowing about IGF1 gives you insight into your dog's size traits, but it’s just one part of the bigger picture when it comes to their health and care.

Full IGF1 gene page →

HMGA2 sits at 71%. HMGA2 is a chromosome-10 size locus that acts together with IGF1, and intermediate frequencies reflect partial commitment to the dominant size variant.

HMGA2what this gene does

HMGA2 is a gene that influences body size in dogs, helping determine how big or small a dog grows.

For your dog: Knowing about HMGA2 helps you appreciate the genetic factors behind your dog's size, but it doesn't signal any health issues.

Full HMGA2 gene page →

SMAD2 sits at 34% at the chromosome-7 height locus.

SMAD2what this gene does

SMAD2 is a gene involved in regulating body size by influencing how cells grow and develop.

For your dog: Knowing about SMAD2 helps understand your dog's size traits but isn't linked to health issues; no immediate action needed.

Full SMAD2 gene page →

LCORL is near-fixed at 88%, the NCAPG/LCORL height locus that is one of the strongest single contributors to canine body size.

LCORLwhat this gene does

LCORL is a gene that influences body size in dogs. It helps determine how big or small a dog might grow.

For your dog: Knowing about LCORL helps you appreciate the genetic factors behind your dog's size, but it’s just one piece of the bigger picture when it comes to health and care.

Full LCORL gene page →

STC2 sits at 79%.

ADAMTS17 is at 89%, near-fixed for the size variant.

ADAMTS17what this gene does

ADAMTS17 is a gene that influences body size and also plays a role in certain eye conditions. It affects the structure of tissues in the eye and elsewhere in the body.

For your dog: If your dog belongs to a breed known to carry ADAMTS17 variants, it’s worth discussing genetic testing and eye exams with your vet to stay ahead of potential issues.

Full ADAMTS17 gene page →

Leg length

The FGF4 retrogene on chromosome 18 sits at 60%. This is the leg-length variant. The intermediate frequency means some dogs in this breed carry the short-legged allele and some do not.

The FGF4 retrogene on chromosome 12 sits at 40%, the chondrodystrophic variant.

Coat type, length, and color

RSPO2 sits at 75% for the furnishings variant. Furnishings (the eyebrow-and-mustache pattern seen in Schnauzers and Wheaten Terriers) vary across the population at this intermediate frequency, and visible expression depends on the specific allele combination each dog carries.

RSPO2what this gene does

RSPO2 influences the texture and appearance of a dog's coat, particularly the presence of 'furnishings' like mustaches and eyebrows. It helps determine whether a dog has that distinctive wiry or textured look.

For your dog: If your dog has those wiry eyebrows or a mustache, RSPO2 is part of the reason—no health worries, just a coat feature worth knowing about.

Full RSPO2 gene page →

FGF5 sits at 79% for the long-coat variant. Coat length is influenced by other loci as well, so intermediate FGF5 frequencies do not always correspond to intermediate visible coat lengths.

FGF5what this gene does

FGF5 is a gene that influences the length of a dog's coat. It acts like a natural switch, telling hair follicles when to stop growing longer fur.

For your dog: If your dog has a notably long or short coat, FGF5 is likely part of the reason—no action needed, but it’s a neat genetic detail to know.

Full FGF5 gene page →

KRT71 sits at 32% for the wavy/curly variant. Coat curl varies across individuals at this intermediate frequency, and visible expression is also influenced by modifier loci.

KRT71what this gene does

KRT71 is a gene that influences the curliness of a dog's coat. It helps determine whether a dog's fur is straight or has a distinctive curl.

For your dog: If your dog has a curly coat, KRT71 is likely part of the reason; it’s a natural variation, not a health concern.

Full KRT71 gene page →

MC1R sits at 79% at the representative SNP. MC1R controls the switch between red-to-gold pigment and black-to-brown pigment, with the e/e homozygous genotype producing the gold-to-red spectrum. Substrate frequencies at this SNP depend on the array's polarity, so visible coat color in the breed is a more reliable indicator than this single number.

MC1Rwhat this gene does

MC1R is a gene that influences coat color in dogs, affecting how pigments are produced in the fur.

For your dog: Knowing about MC1R gives insight into your dog's coat color but doesn't relate to health issues.

Full MC1R gene page →

Ears

MSRB3 sits at 78% for the drop-ear allele, which is why ear set varies across the breed.

MSRB3what this gene does

MSRB3 is a gene involved in the development of ear shape and structure in dogs.

For your dog: Understanding MSRB3 helps explain why your dog's ears look the way they do, but it isn't linked to any health issues.

Full MSRB3 gene page →

Skull shape

BMP3 sits at 65%, contributing to the breed's moderate, mesaticephalic head shape rather than the extreme brachycephalic form.

BMP3what this gene does

BMP3 is a gene that influences the shape of a dog's skull, particularly contributing to a shorter, broader head shape known as brachycephaly.

For your dog: If your dog has a broad, short skull, it's worth discussing with your vet how this might impact their health, even though BMP3 isn't directly tied to illness.

Full BMP3 gene page →

SMOC2 sits at 66%, contributing to the breed's moderate head shape.

SMOC2what this gene does

SMOC2 influences the shape of a dog's skull, particularly affecting how flat or short the face appears.

For your dog: If your dog has a short nose, it's worth discussing with your vet how this trait might impact their health over time.

Full SMOC2 gene page →
Mendelian-disease genetics

What genetic diseases do Portuguese Water Dogs carry?

From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), Portuguese Water Dogs carry 4 of them at observable frequency. Carrier frequency is not clinical risk. Most recessive variants require two copies for disease expression; many dominant variants show incomplete penetrance. Read this as a population fingerprint of what's in the gene pool, not a per-dog prediction.

Chondrodystrophy and Intervertebral Disc Disease Risk (CDDY)
Autosomal dominant
high 10.4%
n = 659 dogs · 1 variant tested · OMIA:000157-9615 · omia.org →
FGF4what this gene does

FGF4 influences leg length by affecting bone growth, leading to shorter legs in certain breeds.

For your dog: If your dog is from a breed known to carry this gene, it's worth discussing spinal health with your vet, but being a carrier doesn’t guarantee problems.

Progressive Rod-Cone Degeneration (prcd-PRA)
Autosomal recessive
low 7.8%
n = 663 dogs · 1 variant tested · OMIA:001298-9615 · omia.org →
PRCDwhat this gene does

PRCD is a gene involved in the health of a dog's retina, the part of the eye that detects light and helps with vision.

For your dog: If your dog belongs to a breed known to carry PRCD changes, it's worth discussing eye health and potential genetic testing with your vet.

GM1 Gangliosidosis (Discovered in the Shiba)
Autosomal recessive
low 0.15%
n = 664 dogs · 3 variants tested · OMIA:000402-9615 · omia.org →
Early-onset PRA (Discovered in the Portuguese Water Dog; EOPRA)
Autosomal recessive
low <0.1%
n = 664 dogs · 2 variants tested · OMIA:001521-9615 · omia.org →
Source: Donner J et al. 2023. Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics 19(2):e1010651 · Evidence: Limited (DTC ascertainment, tag-SNP proxy) · Confounding MEDIUM · License CC-BY-4.0 · Phene IDs from OMIA (Sydney School of Veterinary Science, The University of Sydney; DOI 10.25910/2AMR-PV70).
Sample size in this breed: 664 dogs from the Donner 2023 cohort.

Which Mendelian variants matter most for Portuguese Water Dogs?

The Mendelian-disease table above lists variants screened in 664 Portuguese Water Dogs (Donner 2023). Four matter most by carrier frequency and penetrance.

Chondrodystrophy and Intervertebral Disc Disease Risk (CDDY)

Chondrodystrophy and Intervertebral Disc Disease Risk in Portuguese Water Dogs is caused by a dominant FGF4 retrogene insertion. Portuguese Water Dogs carry this variant at 10.4% (n=659) but do not express the classical chondrodystrophic phenotype, shortened limbs and barrel chest, that defines Dachshunds and Corgis. The breed standard shows normal leg length. The primary clinical concern in Portuguese Water Dogs is intervertebral disc disease risk, not visible limb shortening, though CDDY penetrance in this breed is not yet fully characterized.

The variant matters because it predisposes to disc herniation in middle age. Affected dogs may present with acute pain, hind-limb weakness, or paralysis. Testing is available through commercial DNA panels. Carriers should be monitored for spinal signs and managed conservatively when possible; affected dogs may require surgical decompression.

Progressive Rod-Cone Degeneration (prcd-PRA)

Progressive rod-cone degeneration in Portuguese Water Dogs is an autosomal recessive retinal condition caused by a mutation in the PRCD gene. Affected dogs typically develop night blindness in mid-life, followed by progressive day-blindness and eventual total vision loss over several years. 7.8% of Portuguese Water Dogs in the Donner cohort carry one copy (n=663).

Testing is straightforward and widely available. Two copies of the variant result in disease; two carriers can produce affected offspring. Breeders use test results to avoid carrier-by-carrier pairings.

GM1 Gangliosidosis (Discovered in the Shiba)

GM1 Gangliosidosis in Portuguese Water Dogs is an autosomal recessive neurodegenerative lysosomal storage disease. Affected dogs show progressive neurological decline, tremor, ataxia, cognitive regression, typically onset in early life. The variant is extremely rare in the breed at 0.15% carrier frequency (n=664).

Testing exists but is not routinely recommended given the rarity. Affected dogs have no treatment; management is supportive care.

Early-onset PRA (Discovered in the Portuguese Water Dog; EOPRA)

Early-onset PRA in Portuguese Water Dogs is an autosomal recessive form of progressive retinal atrophy caused by a variant specific to this breed. Affected dogs develop vision loss earlier and more rapidly than in prcd-PRA. The variant is extremely rare at less than 0.1% carrier frequency (n=664).

Testing is available but rarely needed given the rarity in the breed.

How should I test my Portuguese Water Dog?

A Portuguese Water Dog-specific panel from a CLIA-accredited lab should cover CDDY (chondrodystrophy/IVDD risk), prcd-PRA, and the breed-specific EOPRA variant. Testing for GM1 Gangliosidosis is optional given its near-absence in the breed. Breeders should prioritize CDDY and prcd-PRA status before pairing dogs.

What should I feed a Portuguese Water Dog?

Feeding a Portuguese Water Dog well means attending to the breed’s CDDY carrier frequency and the modest joint-health implications that follow. 10.4% of the breed carries the FGF4 retrogene, which predisposes to intervertebral disc disease.

Weight management and joint support are the keystones. Portuguese Water Dogs were bred for full-day water work in the Atlantic, and their metabolism expects sustained activity. A pet Portuguese Water Dog eating a sedentary maintenance diet is being overfed for their actual job. Overweight predisposes to disc herniation; lean body condition is protective. The NRC 2006 calcium-to-phosphorus ratio guideline (1.1:1 to 2:1 for adult dogs) applies here as it does in all breeds, but the discipline of holding weight in the normal range matters more in carriers of CDDY.

A grain-inclusive, protein-appropriate adult formula is the conservative default. The breed has no documented FDA-flagged diet-disease associations like those seen in some other breeds. A diet with adequate omega-3 fatty acid content (supporting joint and skin health) and appropriate caloric density for moderate activity is sufficient. Portuguese Water Dogs have a single-layer, water-resistant coat with no undercoat; occasional omega-3 supplementation may benefit dogs with dry skin, though most thrive on a balanced commercial diet.

Life-stage feeding reflects the breed’s maturity arc. A medium-breed puppy formula with controlled growth rate (calcium 1.0-1.8% dry matter, phosphorus 0.8-1.6% dry matter per NRC 2006) is appropriate during the growth window. Adult maintenance should track actual activity level. Portuguese Water Dogs who participate in dock diving, swimming, or water trials will benefit from slightly elevated protein and fat (20-25% crude protein, 12-15% crude fat) to fuel sustained work. Senior dogs should shift to lower-calorie formulations and may benefit from joint-support supplements if CDDY-related disc disease emerges.

What we don’t know

The breed’s small atlas cohort (n=42 dogs) limits our power to detect rare variants and to track long-term health outcomes across the lifespan. We do not yet have breed-specific median lifespan data from prospective follow-up studies.

CDDY penetrance in Portuguese Water Dogs is not fully characterized. The variant is present at 10.4%, but we do not know what fraction of carriers become symptomatic and at what age. The breed’s water-work heritage may modulate risk; the high activity demands in the breed’s working lineages might either protect against disc herniation through maintained spinal musculature or increase risk through impact on water entries and exits. The honest answer is we do not yet have the longitudinal data to settle this.

Cancer rates, neurological disease frequency, and other age-related conditions lack breed-specific epidemiological surveys. The breed-club health resources would be the first source for these questions, but published studies are thin.

Frequently asked questions about Portuguese Water Dogs

Are Portuguese Water Dogs good swimmers? Yes. The breed was developed along the Portuguese coast to herd fish and retrieve nets, and they have water-resistant single-layer coats and webbing between their toes. Most take naturally to water and enjoy aquatic work or play.

How long do Portuguese Water Dogs live? The Portuguese Water Dog Club of America cites a typical lifespan of 11 to 13 years (pwdca.org). The atlas cohort is too small (n=42) to establish a robust median from prospective follow-up data.

What is the most common health problem in Portuguese Water Dogs? No single condition dominates the health picture the way cancer does in some breeds. Intervertebral disc disease risk is present in 10.4% of the breed via CDDY carrier status (Donner 2023, n=659), and progressive retinal atrophy (prcd-PRA) carrier frequency is 7.8% (Donner 2023, n=663). Both are manageable with monitoring and preventive care.

Should I do a DNA test on my Portuguese Water Dog? For breeding stock, yes. A panel covering CDDY, prcd-PRA, and the breed-specific EOPRA variant is the standard of care. For pet dogs, testing answers questions about disc-disease risk and vision loss risk but does not change management unless two copies of a recessive variant are detected.

What is the best diet for a Portuguese Water Dog? A grain-inclusive adult formula matched to actual activity level is the default. Portuguese Water Dogs are prone to weight gain if overfed for a sedentary lifestyle. Lean body condition is protective against intervertebral disc disease. If your dog swims or works regularly, slightly elevated protein (20-25%) and fat (12-15%) support sustained activity.

Are Portuguese Water Dogs prone to ear infections? The breed has floppy ears and water-loving tendencies, which together create a moisture-trapping environment. Regular ear cleaning after swimming or bathing is standard preventive care. No genetic predisposition to infection has been documented in the breed-specific literature.

Do Portuguese Water Dogs need a lot of exercise? Yes. The breed was developed for full-day water work and retains that metabolic expectation. A sedentary pet Portuguese Water Dog is at higher risk of obesity and disc disease. Aim for at least an hour of sustained activity daily, ideally including swimming or retrieving.

What are Portuguese Water Dogs like with children? Portuguese Water Dogs are typically affectionate and playful with families. Their retrieving drive and water enthusiasm make them strong playmates for older children. Young puppies can be mouthy during play and benefit from supervision with toddlers, as with all energetic breed puppies.

A gift to human medicine

Portuguese Water Dogs are a natural model for human disease

Because the same genes cause the same conditions across species, the inherited conditions documented in Portuguese Water Dogs help researchers understand, and work toward treating, the human diseases they model. This is the dog advancing human medicine. The breed models the human disease; it does not have it, and this is not a prediction for your dog.

Human equivalents via OMIA → Mondo / OMIM. Model-of, not identity.
Documented in OMIA

Every condition recorded in the Portuguese Water Dog

Beyond the testable carriers above, OMIA's literature catalogue records 9 genetic conditions in the Portuguese Water Dog, 7 of which have a known human equivalent. This is the documented landscape across all Portuguese Water Dogs ever studied, not a prediction for any one dog.

Online Mendelian Inheritance in Animals (OMIA); Nicholas, Tammen & Sydney Informatics Hub, DOI 10.25910/2AMR-PV70
Documented in the breed's literature is not carrier status and not a forecast for an individual dog. Human equivalents are mapped via Mondo/OMIM. Carrier frequencies (above) are the separately-measured testable subset (Donner 2023).
The data behind this page

Where every number on this page came from.

This page draws on three primary data sources. Carrier frequencies for the Mendelian section come from Donner et al. 2023 (CC-BY-4.0). We grade these data at evidence Limited because the cohort is a direct-to-consumer ascertainment, which biases toward owners who chose to test their dogs. The panel also uses tag-SNP proxies for some variants rather than direct causal-variant assays. Limited is a study-design grade, not a quality grade: the Donner cohort is the largest open canine-genotype dataset in existence and we are grateful for it. We rate the confounding MEDIUM.

Population-genetic dimensions (heterozygosity, intra-breed PCA distance, nearest neighbors, trait-locus frequencies) come from CanVAS (Brundage 2026), harmonized through the Sniff Atlas. The exact release date and verification commit are pinned at the bottom of the page so a researcher can trace a number back to a specific snapshot. The disease-gene-variant graph comes from OMIA (Online Mendelian Inheritance in Animals; Nicholas, Tammen, and the Sydney Informatics Hub at the Sydney School of Veterinary Science, The University of Sydney; retrieved April 2026, DOI 10.25910/2AMR-PV70).

What this page does not yet have. Inheritance modes and per-disease penetrance evidence from Donner 2023 are now in the structured data for every variant the panel covers. Mondo, OMIM, Ensembl, and HGNC cross-references on gene pages remain pending, they arrive in December 2026 alongside the imputed 9.67M-variant CanVAS dataset via the OMIA SQL dump absorption. Until then, gene IDs carry NCBI Gene and OMIA phene URLs only; the wider human-homolog and disease-ontology cross-reference set fills in with that release.

How to cite this page. The computed dimensions on this page are derived from the open Sniff Atlas v1.0.1 (Gehring 2026, doi:10.5281/zenodo.20566358, CC-BY 4.0). Full citation formats including BibTeX, RIS, and CITATION.cff at sniff.world/cite.

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References
  1. Donner J, Freyer J, Davison S, Anderson H, Blades M, Honkanen L, et al. (2023). Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics 19(2):e1010651. doi:10.1371/journal.pgen.1010651
  2. Brundage J, et al. (2026). CanVAS: a harmonized canine variant atlas. bioRxiv. doi:10.64898/2026.04.13.718238
  3. Nicholas, F.W., Tammen, I., & Sydney Informatics Hub. (2026). Online Mendelian Inheritance in Animals (OMIA) [dataset]. The University of Sydney. https://omia.org. doi:10.25910/2AMR-PV70 (retrieved April 2026).
Last updated
Sources: CanVAS (Brundage 2026) · Donner 2023 · OMIA