C01AE6BB-A9D5-440C-8926-081BD9644930.png

What Does Carrier's Mean in My New Pup

Paws for Thought

Rip Carries DM - About Degenerative Myelopathy

What does this result mean?

Because this variant is inherited in an autosomal recessive manner (meaning dogs need two copies of the variant to develop the disease), Rip is unlikely to develop this condition due to the variant.

Impact on Breeding:

Your dog carries this variant and will pass it on to ~50% of his offspring. You can email breeders@embarkvet.com to discuss with a genetic counselor how the genotype results should be applied to a breeding program.

What is DM ? 

The dog equivalent of Amyotrophic Lateral Sclerosis, or Lou Gehrig’s disease, DM is a progressive degenerative disorder of the spinal cord. Because the nerves that control the hind limbs are the first to degenerate, the most common clinical signs are back muscle wasting and gait abnormalities.

When signs & symptoms develop in affected dogs:

Affected dogs do not usually show signs of DM until they are at least 8 years old.

Genetic Testing Tips:

Genetic testing of the SOD1 gene in Australian shepherds will reliably determine whether a dog is a genetic Carrier of degenerative myelopathy. Degenerative Myelopathy is inherited in an Autosomal Recessivemanner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the SOD1 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms may not appear until adulthood and some at-risk/affected dogs do not develop the disease, genetic testing should be performed before breeding. Until the exact modifying environmental or genetic factor is determined, genetic testing remains the only reliable way to detect neurological disease associated with this mutation prior to death. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Australian shepherds that are not carriers of the mutation have no increased risk of having affected pups.

Willa Carries Progressive Retinal Atrophy - About PRA-crd4/cord1

What does this result mean?

Because this variant is inherited in an autosomal recessive manner (meaning dogs need two copies of the variant to develop the disease), Willa is unlikely to develop this condition due to the variant.

Impact on Breeding:

Your dog carries this variant and will pass it on to ~50% of her offspring. You can email breeders@embarkvet.com to discuss with a genetic counselor how the genotype results should be applied to a breeding program.

What is PRA-crd4/cord1 ? 

PRA-CRD4/cord1 is a retinal disease that causes progressive, non-painful vision loss over a 1-2 year period. The retina contains cells, called photoreceptors, that collect information about light and send signals to the brain. There are two types of photoreceptors: rods, for night vision and movement, and cones, for day vision and color. This type of PRA leads to early loss of cone cells, causing day blindness before night blindness.

When signs & symptoms develop in affected dogs 

The earliest ophthalmic signs are typically present by 6 months of age. There is a wide range in the age of when dogs become clinically affected, although the average age is approximately 5 years. Dogs as young as 6 months may be blind, while dogs as old as 10 may still have vision.

Genetic Testing Tips:

Genetic testing of the PRCD gene will reliably determine whether a dog is a genetic Carrier of PRA-prcd. PRA-prcd is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of being a carrier of the PRCD gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms do not appear until adulthood, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups. However, because there are multiple types of PRA caused by mutations in other genes, a normal result in PRCD does not exclude PRA in a pedigree.

Risa Carries MDR1 - About Multiple Drug Sensitivity

What does this result mean?

Because this variant is inherited in an autosomal recessive manner (meaning dogs need two copies of the variant to develop the disease), Risa is unlikely to develop this condition due to the variant.

Impact on Breeding:

Your dog carries this variant and will pass it on to ~50% of her offspring. You can email breeders@embarkvet.com to discuss with a genetic counselor how the genotype results should be applied to a breeding program.

What Is MDR1?

Multidrug resistance 1, also called MDR1, is an inherited condition affecting several breeds of dogs, especially herding dogs or descendants of herding breeds. The Mutation in the ABCB1 gene associated with MDR1 causes dysfunction of P-glycoprotein, which is responsible for removing certain drugs and toxins from the body. Clinical signs are most commonly associated with distribution of the drug in the central nervous system. MDR1 is inherited in an autosomal incomplete dominant manner in dogs meaning that dogs only need to inherit one copy of the mutated gene to be at an increased risk of developing adverse reactions to certain medications. Though adverse reactions to certain drugs are most commonly seen in dogs having two copies of the mutated gene, Carrier dogs can also experience drug sensitivities and dosages need to be adjusted accordingly. Thus, dogs that have one or two copies of the mutation are considered at-risk for adverse drug reactions. If an at-risk dog is treated with one of several common drugs (see below*), they are at risk of developing neurologic symptoms that could range from tremors, excess salivation, anorexia, and blindness to coma and even death. Because of the defective ability to metabolize specific drugs, these drugs can be lethal even at low doses. The MDR1 mutation does not cause adverse effects in dogs unless the dog is exposed to these drugs. Therefore, veterinarians should be notified when a dog is at risk for multidrug resistance 1 prior to administration of any medications.

*Drugs known to cause neurological signs related to the MDR1 mutation:
Acepromazine, butorphanol, doxorubicin, emodepside, erythromycin, ivermectin, loperamide, milbemycin, moxidectin, rifampin, selamectin, vinblastine and vincristine.


In addition to this list, there are many other drugs known to be removed from the central nervous system via the P-glycoprotein mechanism in humans. However, reports of neurological dysfunction related to drugs other than those listed here are scarce in dogs. Please consult your veterinarian prior to giving drugs to known multidrug resistance carriers, affected dogs, or untested dogs of breeds commonly affected with this condition.

Genetic Testing Tips:

Genetic testing of the ABCB1 gene will reliably determine whether a dog is a genetic Carrier of multidrug resistance 1. Multidrug resistance 1 is inherited in an autosomal incomplete dominant manner in dogs meaning that dogs only need to inherit one copy of the mutated gene to be at an increased risk of developing the disease. Though adverse reactions to certain drugs are most commonly seen in dogs having two copies of the mutated gene, carrier dogs can also experience drug sensitivities and dosages need to be adjusted accordingly. Thus, dogs that have one or two mutant copies of the gene are considered at-risk for adverse drug reactions. When carriers of this Mutation are bred with another dog that also is a carrier of the same mutation, there is risk of having affected pups. For each pup that is born to this pairing, there is a 25% chance that the puppy will inherit two copies of the mutation and a 50% chance that the puppy will inherit one copy of the mutation and, in either case, may be susceptible to having adverse drug reactions. Reliable genetic testing is important for determining breeding practices. Because symptoms do not appear unless dogs are exposed to certain drugs, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups when bred to a dog that is also clear for this mutation.

Get in Touch