Details about the disease
MDR1 is an inherited condition that makes affected dogs particularly sensitive to drugs like ivermectin (anti-parasitic) and loperamide (opioid to treat diarrhoea). In normal dogs the blood/brain barrier protects the brain cells from various drugs and toxins. P-glycoprotein is a protein which physically pumps drugs and toxins from the cerebrospinal fluid (serum-like fluid that circulates through the brain ventricles and spinal cord cavity) back into the blood circulation. The MDR-1 mutation results in an inactive P-glycoprotein which means that drugs and toxins can accumulate in the cerebrospinal fluid and begin to inhibit brain activity.
Clinical signs
The result is that exposure of affected dogs to such drugs may be an illness requiring an extended hospital stay - or even death.
How is it inherited?
The disease is described as an autosomal-recessive condition. This means that a dog must inherit two copies of an abnormal gene (one from its mother and one from its father) before its health is affected. A dog that inherits only one copy of the abnormal gene (from its mother or its father) will have no signs of the disease, but will be a carrier and may pass the gene on to any offspring.
Which laboratories we record and publish the results from?
To find out which laboratories The Kennel Club is able to record results from, and which laboratories will send results directly to The Kennel Club, please refer to our website.
Please be aware, The Kennel Club has a set of criteria that we request DNA testing laboratories to meet to enable us to record their results, helping to maintain and protect the integrity of results that appear on a dog’s record. We strongly advise that customers ensure their chosen laboratory is included on our list if they wish The Kennel Club to record and publish the results. Results from laboratories not included on this list will not be recorded.
Breeding advice and what your dog's results mean
If, once your dog is DNA tested, you would like to find out what their DNA test results mean, or how to select the right mate to avoid producing affected puppies, then please read our breeding advice and DNA testing information.
How to find out if a potential mate has been DNA tested
The Kennel Club’s Health Test Results Finder allows you to find the results of DNA tests carried out as part of The Kennel Club's official DNA testing schemes for any dog on The Kennel Club’s Breed Register.