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Maltese

Lifespan
13.1 years
95% CI 12.6 to 13.5 · McMillan 2024, n=2,021
Most carried variant
Chondrodystrophy and Intervertebral Disc Disease Risk
3.5% of 2,403 tested · Donner 2023
Behind this page
96 dogs
in the atlas · 2,413 tested for variants
Also carried:Exercise-Induced Collapse · 2.2%Von Willebrand's Disease, Type 1 · 2%

Malteses have a cited life expectancy of 13.1 years (McMillan 2024 / VetCompass, n=2,021, 95% CI 12.6 to 13.5). The most carried tested variant is Chondrodystrophy and Intervertebral Disc Disease Risk, in 3.5% of 2,403 Malteses tested (Donner 2023), then Exercise-Induced Collapse (2.2%) and Von Willebrand's Disease, Type 1 (2%).

Maltese
Photo: Sannse · CC BY-SA 3.0 · Wikimedia

Also known as Canis familiaris Maelitacus and Maltese lion puppy.

See in the atlas → From CanVAS
Mendelian-disease genetics

What genetic diseases do Malteses carry?

From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), Malteses carry 20 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
moderate 3.5%
n = 2,403 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.

Bald Thigh Syndrome (Discovered in Sighthounds)
Autosomal recessive
low 8.3%
n = 12 dogs · 1 variant tested · OMIA:002168-9615 · omia.org →
IGFBP5what this gene does

IGFBP5 is a gene that helps regulate growth factors involved in tissue development and repair.

For your dog: If you have a sighthound, it’s worth mentioning IGFBP5-related risks to your vet, but being a carrier doesn’t mean your dog will develop the syndrome.

Cystinuria Type I-B (SLC7A9 p.A217T)
Autosomal recessive (Incomplete penetrance)
marker disputed 5.3%
n = 2,413 dogs · 2 variants tested · OMIA:001880-9615 · omia.org →
SLC7A9what this gene does

SLC7A9 is a gene that helps transport certain amino acids in the kidneys. It plays a role in how the body handles cystine, an amino acid that can form crystals.

For your dog: If your dog is a carrier, it’s worth discussing with your vet to monitor urinary health and catch any issues early.

Exercise-Induced Collapse (EIC)
Autosomal recessive (Incomplete penetrance)
low 2.2%
n = 2,413 dogs · 1 variant tested · OMIA:001466-9615 · omia.org →
DNM1what this gene does

DNM1 is a gene that helps nerve cells communicate properly by managing how they send signals during muscle activity.

For your dog: If your dog belongs to one of the breeds known to carry this gene variant, it's worth discussing EIC with your vet, especially if your dog is very active or shows signs of weakness during exercise.

Von Willebrand's Disease, Type 1 (vWD 1)
Autosomal recessive
low 2.0%
n = 2,413 dogs · 1 variant tested · OMIA:001057-9615 · omia.org →
Progressive Rod-Cone Degeneration (prcd-PRA)
Autosomal recessive
low 0.85%
n = 2,408 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.

Cystinuria Type I-A (SLC3A1 p.I192V)
Autosomal recessive
low 0.56%
n = 2,413 dogs · 3 variants tested · OMIA:000256-9615 · omia.org →
SLC3A1what this gene does

SLC3A1 is a gene that helps transport certain amino acids in the kidneys. It plays a key role in preventing the buildup of cystine, which can form stones.

For your dog: If your dog is from a breed known to carry SLC3A1 variants, it’s worth discussing cystinuria risks with your vet, especially if urinary issues arise.

Degenerative Myelopathy (DM)
Autosomal recessive (Incomplete penetrance)
low 0.54%
n = 2,413 dogs · 1 variant tested · OMIA:000263-9615 · omia.org →
SOD1what this gene does

SOD1 is a gene that helps protect cells from damage caused by harmful molecules called free radicals.

For your dog: If your dog is a carrier of SOD1 variants, it's worth discussing with your vet, but remember carrier status doesn't mean your dog will get the disease.

Prekallikrein Deficiency
Autosomal recessive
low 0.52%
n = 2,413 dogs · 1 variant tested · OMIA:000819-9615 · omia.org →
KLKB1what this gene does

KLKB1 is a gene that helps produce prekallikrein, a protein involved in blood clotting and inflammation.

For your dog: If your dog is from a breed known to carry KLKB1 variants, it's worth asking your vet about blood clotting tests, especially before surgeries.

Glycogen Storage Disease, Type Ia (GSD Ia)
Autosomal recessive
low 0.33%
n = 2,413 dogs · 1 variant tested · OMIA:000418-9615 · omia.org →
Dilated Cardiomyopathy risk factor (Discovered in the Doberman Pinscher; PDK4-related)
Autosomal dominant (Incomplete penetrance)
marker disputed 0.29%
n = 2,413 dogs · 2 variants tested · OMIA:000162-9615 · omia.org →
PDK4what this gene does

PDK4 helps regulate how cells use energy, especially in the heart muscle.

For your dog: If your dog is one of the breeds known to carry this gene, it’s worth discussing heart health with your vet, but being a carrier doesn’t mean your dog will develop disease.

Primary Ciliary Dyskinesia (Discovered in the Old English Sheepdog; CCDC39-related PCD)
Autosomal recessive
low <0.1%
n = 2,413 dogs · 1 variant tested · OMIA:001540-9615 · omia.org →
Bleeding disorder (Discovered in the Greater Swiss Mountain Dog; P2RY12-related)
Autosomal recessive
low <0.1%
n = 2,412 dogs · 1 variant tested · OMIA:001564-9615 · omia.org →
P2RY12what this gene does

P2RY12 is a gene that helps control how platelets stick together to form blood clots, which is essential for stopping bleeding.

For your dog: If your dog is from one of these breeds, it’s worth asking your vet about P2RY12 to understand any potential bleeding risks, especially before surgery or injury.

Complement 3 (C3) Deficiency
Autosomal recessive
low <0.1%
n = 2,413 dogs · 1 variant tested · OMIA:000155-9615 · omia.org →
Cone-Rod Dystrophy (cord1-PRA/crd4)
Autosomal recessive (Incomplete penetrance)
low <0.1%
n = 2,413 dogs · 1 variant tested · OMIA:001432-9615 · omia.org →
RPGRIP1what this gene does

RPGRIP1 is a gene involved in the function of photoreceptor cells in the eye, which help dogs see in different light conditions.

For your dog: If your dog belongs to a breed known to carry RPGRIP1 mutations, it’s worth discussing with your vet to understand the risks and monitor eye health.

Congenital Dyshormonogenic Hypothyroidism with Goiter (Discovered in the Shih Tzu)
Autosomal recessive
low <0.1%
n = 2,413 dogs · 1 variant tested · OMIA:002174-9615 · omia.org →
Hyperuricosuria (HUU)
Autosomal recessive
low <0.1%
n = 2,413 dogs · 1 variant tested · OMIA:001033-9615 · omia.org →
SLC2A9what this gene does

SLC2A9 is a gene that helps regulate uric acid levels in a dog's body. It plays a role in how the kidneys handle this substance.

For your dog: If your dog is one of the breeds known to carry this gene variant, it’s worth discussing with your vet to understand any potential urinary health concerns.

Primary Lens Luxation (PLL)
Autosomal recessive
Pathogenic low <0.1%
n = 2,413 dogs · 2 variants tested · OMIA:000588-9615 · omia.org →
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 →
Progressive Retinal Atrophy (Discovered in the Giant Schnauzer; NECAP1-related)
Autosomal recessive
low <0.1%
n = 2,413 dogs · 1 variant tested · OMIA:002198-9615 · omia.org →
Pyruvate Kinase (PK) Deficiency (Discovered in the Beagle)
Autosomal recessive
low <0.1%
n = 2,413 dogs · 4 variants tested · OMIA:000844-9615 · 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: 2,413 dogs from the Donner 2023 cohort.
In plain terms

What these results mean for a Maltese

Chondrodystrophy and disc disease risk (CDDY)

3.5% of Malteses in the Donner 2023 cohort carried it (n=2,403).

  • Two extra copies of a growth gene, FGF4, shape dog legs and spines. The one on chromosome 12 is the one tied to disc disease; the one on chromosome 18 shortens legs.
    OMIA 000157-9615

    “Two FGF4 retrogenes (FGF4L1 on chromosome 18 and FGF4L2 on chromosome 12) have been identified to cause dwarfism across many dog breeds.” OMIA 000157-9615

    “Brown et al. (2017) reported that an FGF4 retrogene insertion in chromosome CFA12” OMIA 000157-9615

  • Carrying it raises risk. It does not say which dog will have a disc problem. In Dachshunds researchers found the test is not a valid risk indicator on its own.
    OMIA 000157-9615

    “the FGF4 retrogene insertion on CFA12 is not a valid risk indicator on its own” OMIA 000157-9615

What to do
Ask your veterinarian what a carrier result changes for your dog. What lowers risk in a carrier is not established in the sources this page draws on.

No test, or a mix
Without a test nobody can say whether a dog carries it. Leg length alone does not tell you: the disc-disease copy and the short-leg copy are different insertions.

SLC7A9 p.A217T (sold as a cystinuria test)

Marker disputed

5.3% of Malteses in the Donner 2023 cohort carried it (n=2,413).

  • The curated record finds no support for this variant causing cystinuria, and the researchers who studied it advise against using it as a test.
    OMIA 001880-9615

    “there appears to be no support for the variant to be causal” OMIA 001880-9615

    “strongly recommend not to use "the variant in SLC7A9 as a test to predict the risk of developing cystinuria in male English bulldogs.” OMIA 001880-9615

What to do
A carrier result for this variant does not predict bladder stones. Straining to urinate or blood in the urine is a reason to see a veterinarian whatever a DNA test says.

No test, or a mix
The curated record gives no reason to test for this variant.

Which Mendelian variants matter most for Malteses?

The Mendelian-disease table above lists 194 variants screened in 2,413 Malteses (Donner 2023). Three rise above the rest by carrier frequency and clinical consequence. The sample size of 2,413 is robust for most variants, though a few rarer variants rest on smaller sub-samples where confidence intervals are wider.

Bald Thigh Syndrome (Discovered in Sighthounds)

Bald Thigh Syndrome is a rare recessive condition causing hair loss, first described in Sighthounds. In Malteses the figure below is a carrier frequency from Donner 2023, not a case series in the breed. Severity ranges from cosmetic to moderately bothersome. The carrier frequency is 8.3%, but the sample size for this variant is small (n=12). Treat this number with caution, it may shift as more Malteses are tested.

Testing exists. The condition is manageable and not life-threatening.

What should I feed a Maltese?

Malteses weigh 4 to 6 pounds adult, which means a missed meal or underfed day can drop their blood sugar into the hypoglycemic range within hours. Feeding frequency and portion precision matter more in this breed than in most others. The toy-breed metabolic requirement is the primary constraint; the breed’s modest genetic-disease burden shapes the secondary choices.

Meal frequency and small portions are non-negotiable. The National Research Council (NRC 2006) uses metabolic body weight to estimate caloric needs. A typical 5-pound adult Maltese needs roughly 150 to 200 kilocalories per day depending on activity level; consult your veterinarian for a precise target. A single meal can lead to dangerous blood-sugar dips between feedings. Two or three meals per day are standard; some owners split the ration into four small offerings.

Choose a formula built for toy breeds, not a diluted large-breed kibble. Toy-breed formulas account for smaller kibble size, faster metabolism, and dental wear patterns. Toy-breed formulas are generally designed for smaller kibble size, faster metabolism, and the caloric density these dogs need. Read the guaranteed analysis on the label. Crude protein should be 18 to 25 percent for adults and 22 to 32 percent for puppies. Fat content of 12 to 15 percent is appropriate for the breed.

Hypoglycemia watch in puppies and underweight adults. If a Maltese misses a meal, watch for lethargy, trembling, or disorientation. Have a small amount of honey or corn syrup on hand and contact your vet immediately if these signs appear. This is not melodrama, it is standard toy-breed protocol. Feed after play or training sessions to stabilize blood sugar.

The 3.5% CDDY carrier frequency is low enough that disc-protective nutrition is standard care, not specialized diet. Keeping any Maltese at a healthy weight reduces mechanical stress on the spine regardless of CDDY status. Maintain a healthy weight and avoid letting puppies jump from heights. A food that supports lean muscle mass (protein-adequate, calorie-controlled) is more important than special supplements. Joint supplements (glucosamine, chondroitin) have weak evidence in dogs but are harmless if added under veterinary guidance.

What we don’t know

The Bald Thigh Syndrome carrier frequency (8.3%) rests on a sample of 12 dogs. This is too small to be confident. As more Malteses are genotyped, this number will either hold or shift significantly. Ask your breeder whether their stock has been tested for this variant.

Exercise-Induced Collapse in Malteses shows zero phenotype confirmation in the Donner dataset (0/2 at-risk homozygous dogs), with a 2.2% single-copy carrier frequency in the population. We do not yet know whether the variant produces clinical disease in this breed or whether the breed context modifies expression. The finding is in the substrate but the functional consequence remains uncertain.

Cancer burden in Malteses is not well characterized. Breed-club health data are limited. Cited life expectancy is 13.1 years (McMillan 2024 / VetCompass), consistent with other toy breeds, but what kills Malteses most commonly and whether breed-specific prevention strategies exist are open questions.

Frequently asked questions about Malteses

Are Malteses prone to hypoglycemia? Yes, especially as puppies. Toy breeds like Malteses have fast metabolisms and can develop dangerously low blood sugar between meals. Feed multiple small meals per day and monitor for lethargy or trembling between feedings. Contact your vet immediately if these signs appear.

How long do Malteses usually live? Cited life expectancy is 13.1 years (McMillan 2024 / VetCompass, n=2,021, 95% CI 12.6 to 13.5). Individual variation is wide; some live into their mid-teens, others shorter. Consistent veterinary care, weight management, and dental hygiene support longevity.

Are Malteses good with children? Malteses are affectionate and playful, but their small size makes them vulnerable to accidental injury from young children. Supervise interactions with children under 8 years old. Malteses are sturdier with older, gentle children.

What should I feed a Maltese puppy? A toy-breed puppy formula with 22 to 32 percent protein, split into three or four small meals per day. Avoid adult kibbles or large-breed formulas, they are not calorie-dense enough for toy-breed growth rates. Feed after play sessions and monitor for signs of hypoglycemia (lethargy, trembling).

Do Malteses have genetic predisposition to intervertebral disc disease? Malteses carry the CDDY variant at 3.5% (Donner 2023, n=2,403), which adds IVDD risk on top of the breed’s general vulnerability from small body size. Weight management and avoiding jumping from heights are core preventive measures for all Malteses, not just carriers.

Temperament

What Malteses tend toward

Tendencies from owner surveys of purebred Malteses — a leaning across the breed, not a prediction for any one dog. A bar’s strength shows how much of that behavior breed actually explains: for most it’s faint, because the rest is your dog, their training, and the life you give them.

Proximity Seekingbreed ~13%
affectionatealoof
n = 25 dogs · Morrill et al. 2022, Science, Darwin's Ark (CC0)
Owner-reported purebreds; each factor n ≥ 25. "Breed ~%" is the share of this behavior explained by breed.
Names & origins

Other names

The Maltese is also recorded as Canis familiaris Maelitacus and Maltese lion puppy.

Identified as Maltese (VBO:0200856) in the Vertebrate Breed Ontology (Mullen et al. 2025, CC-BY 4.0) · registry IDs FCI 65 · iDog 155 · VeNom 22450.

For researchers Population genetics, disease models and every recorded condition Open the research detail for the Maltese
What the atlas says about Maltese

In the atlas, the Maltese clusters consistently as Maltese (100% of the 96 dogs here).

Low breed predictability score (0.24), individual dogs of this breed vary widely in genetics, suggesting active substructure or sub-population diversity.

Median lifespan is 12.05 years, about 1.5 years shorter than a typical dog of 3.5 kg, one of the larger gaps in the atlas.

Genetic dimensions · CanVAS atlas

What the atlas genotypes say about Maltese

Computed from the 14,478 CanVAS dogs in the Atlas, on an imputed genotype backbone: 77,215 directly typed sites per dog, imputed to 9.67 million variants.

The confidence below counts dogs, not reads: it is the size of the sample, and it is separate from how the genotypes were measured.

Dogs in the Atlas
96Founders
77 from Hayward2016, 10 from Spatola, 8 from Shannon
Genetic diversity
0.31Moderate
Mean heterozygosity across the breed. 49th most diverse of 107 ranked populations.
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: 30.10 · 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 Toy 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
13.1years (life expectancy)
95% CI 12.6–13.5 · VetCompass, McMillan 2024, n=2,021. 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.

n = 96 dogs · high sample · CanVAS (Brundage 2026) · Sniff Atlas
A gift to human medicine

Malteses are a natural model for human disease

Because the same genes cause the same conditions across species, the inherited conditions documented in Malteses 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. The named gene is the canine locus, not a claim that a pet has the human disease.
Documented in OMIA

Every condition recorded in the Maltese

Beyond the testable carriers above, OMIA's literature catalogue records 5 genetic conditions in the Maltese, 4 of which have a known human equivalent. This is the documented landscape across all Malteses 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 in the structured data for every variant the panel covers. Mondo, OMIM, Ensembl, and HGNC cross-references live on the gene and disease pages this page links to, rather than being repeated here. What is still absent from this breed page is anything not in the cited panel, and each such gap carries its cause where it appears.

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 DM (2026). CanVAS: A Harmonized and Imputed 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