•	Tobi's test results show Bullmastiff / Siberian Husky / Boxer / Mastiff Cross crossed with Bullmastiff / American Staffs. Terrier Mix with a portion of the ancestry mixed beyond three generations.

•	The test results indicate that Tobi carries no copies of the MDR1 mutation. Please refer to the detailed MDR1 Results page later in this report.

•	Tobi was tested for over 140 disease-causing mutations – all results were negative.

•	We predict Tobi’s ideal weight range to be:

•

76 - 120 lbs

MDR1 Normal/Normal - These dogs do not have the MDR1 mutation. They will not pass on the mutant gene to their offspring.

MDR1, or Multidrug Resistance-1 is a genetic mutation found in many of the herding breeds, some sighthound breeds and many mixed-breed dogs. The MDR1 gene is responsible for production of P-glycoprotein, which is a transport pump that plays an important role in limiting drug absorption and distribution (particularly to the brain), and in enhancing the excretion of many drugs used in dogs.

Some dogs, particularly herding breeds or mixed-breed dogs with herding breed ancestry, may have a mutation in the MDR1 gene that impairs the dog’s ability to limit the absorption and distribution of many drugs. These dogs are also slower to eliminate drugs from the body that are normally transported by P-glycoprotein. All dogs have two copies of this gene, and dogs with mutations in both copies will be much more sensitive to some commonly used drugs. Even dogs with only one copy of the mutation, however, are more sensitive to drugs than dogs with two normal MDR1 genes. Therefore, it is helpful to talk to your clients about this testing opportunity so that you can provide your canine patients with the best possible care.

There is currently no agreement among veterinarians and veterinary anesthesiologists regarding changes in medication dosing (including anesthetic medications) for dogs that carry the MDR1 (also known as ABCB1) mutation. It is always recommended to monitor pets closely for any unexpected side effect of any medication, including anesthetic agents. Dr. Katrina Mealey (Washington State University) currently recommends a 25% reduction in acepromazine and butorphanol in nor/mut genotypes and a 50% reduction in mut/mut genotypes. However, these recommendations are only general guidelines and should not be considered a Banfield standard of care at this time. All anesthetic agents should be dosed to effect and close pet monitoring remains crucial.

It is always up to the veterinary team to determine the most appropriate pharmaceutical option for their patients. Owners of pets with an MDR1 mutation should be educated about risks of all medications (list provided). It is recognized that dosing of FDA approved macrocyclic lactone-containing heartworm preventatives does not need to be altered in pets with MDR1 mutations (1-3). Higher dosages of these compounds (eg. for treatment of demodectic mange) should be used cautiously in these pets.

Take each pet's unique history, prior pharmaceutical history, and concurrent medications into account. Consider consultation with a veterinary specialist as appropriate.

For more information about MDR1 contact Mars Veterinary at 1-888-597-3883 or customercare@marsveterinary.com, Or visit the Washington State University School of Veterinary Medicine at http://vcpl.vetmed.wsu.edu/.

MDR1 Genetic Screening Information

Drugs affected by the MDR1 mutation	Breeds affected by the MDR1 mutation (frequency %):
Acepromazine Butorphanol Erythromycin Ivermectin Loperamide Milbemycin Moxidectin Rifampin Selamectin Many chemotherapeutic agents; please consult with Mars Veterinary or WSU for dosing information.	Australian Shepherd 50% Australian Shepherd, Mini 50% Border Collie 5% Collie 70% English Shepherd 15% German Shepherd 10% Herding Breed Cross 10% Long-haired Whippet 65% McNab 30% Mixed Breed 5% Old English Sheepdog 5% Shetland Sheepdog 15% Silken Windhound 30%

References

1.	Geyer J, Janko C. Treatment of MDR1 Mutant Dogs with Macrocyclic Lactones. Curr Pharm Biotech, 2012;13:969-986.
2.	Sherman JG, Paul AJ, Firkins LD. Evaluation of the safety of spinosad and milbemycin 5-oxime orally administered to Collies with the MDR1 gene mutation. Am J Vet Res. 2010 Jan;71(1):115-9.
3.	Mealey, K. Adverse Drug Reactions in Veterinary Patients Associated with Drug Transporters. Vet Clin Sm Anim, 2013; 43:1067-1078.

Disease	Gene	Mode of inheritance	Test Results
Phosphofructokinase Deficiency	PFKM	recessive	negative
Degenerative Myelopathy	SOD1	recessive with incomplete penetrance	negative
Exercise-Induced Collapse	DNM1	recessive	negative
Hyperuricosuria	SLC2A9	recessive	negative
Pyruvate Kinase Deficiency	PKLR_West Highland White Terrier	recessive	negative
Cystinuria Type I-A	SLC3A1_Newfoundland	recessive	negative
Pyruvate Dehydrogenase Phosphatase 1 Deficiency	PDP1	recessive	negative
Neonatal Encephalopathy with Seizures	ATF2	recessive	negative
L-2-Hydroxyglutaric Aciduria	L2HGDH_Staffordshire Bull Terrier	recessive	negative
Early-Onset Progressive Polyneuropathy	NDRG1_Greyhound	recessive	negative
von Willebrand's Disease (vWD) Type 1	VWF	recessive but may also affect some heterozygotes	negative
Factor VII Deficiency	F7	recessive	negative
Primary Lens Luxation	ADAMTS17	recessive but may also affect some heterozygotes with incomplete penetrance	negative

These genetic health screens were developed in partnership with Genoscoper® Laboratories (www.genoscoper.com) for use in the Banfield® Canine Genetic Analysis™ test.