Lacy Dog
The tested variant with the highest allele frequency is Factor VII Deficiency, at 11% among the 32 Lacy Dogs tested (Donner 2023; gene copies, not dogs), then Collie Eye Anomaly (9.4%) and MDR1 (1.6%).
Which disease variants turn up in Lacy Dogs?
From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), 8 turn up in Lacy Dogs at observable frequency. The figure beside each is its allele frequency. Of the gene copies tested in this breed, the share that carry the variant. Every dog carries two copies, so this is not the share of dogs. It 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.
F7what this gene does
The F7 gene helps produce a protein important for blood clotting, which stops bleeding when dogs get injured.
For your dog: If your dog is from a breed known to carry F7 variants, it's worth mentioning to your vet before any surgery or if you notice unusual bleeding.
ABCB1what this gene does
ABCB1 is a gene that helps control how certain drugs are processed and cleared from a dog's body.
For your dog: If your dog is from a breed that carries this gene variant, ask your vet about medication sensitivities before giving any new drugs.
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.
NHEJ1what this gene does
NHEJ1 is a gene involved in repairing breaks in DNA, helping maintain the integrity of genetic information in cells.
For your dog: If your dog belongs to one of the breeds known to carry this gene variant, it's worth discussing testing with your vet to understand any potential eye health risks.
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.
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.
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.
What these results mean for a Lacy Dog
1.6% of Lacy Dogs in the Donner 2023 cohort carried it (n=32).
- MDR1 is a drug sensitivity, not a disease. A dog with the variant lacks a pump that keeps certain drugs out of the brain.
OMIA 001402-9615
“Multidrug resistance 1 is caused by a lack of P-glycoprotein drug transporter in the blood-brain barrier, which is characterized by neurotoxicity after administration of certain drugs.” OMIA 001402-9615
- Heartworm prevention is safe. At the dose on the label, every FDA-approved heartworm preventive sold in the United States is safe even for a dog with two copies of the variant.
Mealey 2008
“at the manufacturer's recommended dose, all FDA-approved heartworm preventive products marketed in the United States are safe, even for dogs with the ABCB1 mutant/mutant genotype” Mealey 2008
- The risk is dose. The same drug family (ivermectin, milbemycin and their relatives) causes toxicity in these dogs at doses other dogs tolerate, and some chemotherapy drugs are handled by the same pump.
Mealey 2008
“renders affected animals extremely susceptible to toxicosis induced by substrate drugs, such as the macrocyclic lactones at doses well below those tolerated by dogs with the wild-type ABCB1 gene” Mealey 2008
“Many drugs used in veterinary medicine are substrates for P-gp, including many chemotherapeutic agents and macrocyclic lactones” Mealey 2008
What to do
Keep heartworm prevention going at the label dose. Tell your veterinarian the dog's MDR1 status before any off-label parasite treatment or chemotherapy.
No test, or a mix
No test yet, or a mix that may have herding ancestry: label-dose heartworm prevention is safe either way. For any higher-dose decision, tell your veterinarian the dog is untested so it can be treated as a possible carrier.
23.4% of Lacy Dogs in the Donner 2023 cohort carried it (n=32).
- This is a marker, not an established cause. The curated record says a test based on it is not a good indicator of heart disease risk even in Dobermans, the breed it was found in.
OMIA 000162-9615
“it is evident that any DNA test based on this marker will not be a good indicator of liability to this disorder in Dobermans” OMIA 000162-9615
What to do
A carrier result for this marker is not, on its own, a reason for heart screening. Heart screening is a conversation with your veterinarian about the breed and the dog.
No test, or a mix
What this marker means in breeds other than the Doberman is not established in the sources this page draws on.
SLC7A9 p.A217T (sold as a cystinuria test)
Marker disputed1.6% of Lacy Dogs in the Donner 2023 cohort carried it (n=32).
- 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.
1.6% of Lacy Dogs in the Donner 2023 cohort carried it (n=32).
- DM is a loss of function in the spinal cord that begins in adulthood and progresses to paralysis of the back legs. There is no treatment that stops it.
OMIA 000263-9615
“This is an adult onset degeneration of the spinal cord that progresses to paraplegia and tetraparesis. There is no successful treatment. A genetic test is available.” OMIA 000263-9615
- Two copies of the SOD1 variant mean at risk, not affected. Some dogs with two copies never show signs.
OMIA 000263-9615
“some homozygous mutant dogs had no signs of degenerative myelopathy, which suggests incomplete penetrance or other causative loci” OMIA 000263-9615
- One copy makes a dog a carrier. In the study that found the variant, every affected dog tested had two copies.
OMIA 000263-9615
“All affected dogs tested were homozygous mutant.” OMIA 000263-9615
What to do
A DNA result is not a diagnosis. Take the result, and any change in how the dog walks, to a veterinarian.
No test, or a mix
Without a test nobody can say how many copies a dog has. A breed's allele frequency describes the breed, not this dog.
For researchers Population genetics, disease models and every recorded condition Open the research detail for the Lacy Dog
Where every number on this page came from.
This page draws on one primary data source. Allele frequencies and sample sizes come from Donner et al. 2023 (CC-BY-4.0), a direct-to-consumer screening cohort, graded Limited as a study design because the dogs were tested at their owners' choice. No genotyped research dogs of this breed are in the three open releases the atlas reads, so the population-genetic sections other breed pages carry are absent here for that reason, not hidden. Conditions recorded for the breed come from OMIA.
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. Cite Donner et al. 2023 (doi:10.1371/journal.pgen.1010651) for every frequency on this page, and OMIA for each condition, with the sample size shown beside the figure.
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- 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
- Brundage DM (2026). CanVAS: A Harmonized and Imputed Canine Variant Atlas. bioRxiv. doi:10.64898/2026.04.13.718238
- 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).