by Krista Waitz October 2008
Reproduced with permission
Addison's disease has been detected in a limited number of the Australian Labradoodles and Labradoodles. Addison's disease is a disease that cannot yet be detected prior to the expression of the disease. The Poodle Club of America and UC Davis (http://cgap.ucdavis.edu/Default.htm) among others is currently funding and undertaking research to detect the DNA specific to Addisons. When discovered this will allow breeders to pinpoint Addisons affected and Addisons carrier dogs prior to the expression of the disease.
Until that time the only available breeding strategy for breeders of any breed where Addisons has been discovered (which includes Poodles and Poodle mixes) is to identify publically and remove from breeding programs dogs that have actually produce Addison's offspring and to study thier pedigrees to understand higher risk pedigree lines. Higher risk pedigree lines would be those that include parents and grandparents of dogs that have Addisons. Due to current research indicating Addisons is both genetic, polygenic (involves multiple genes) and autosomal recessive (must be inherited from both parents); these ancestor dogs could carry the disease.
Two actions will greatly enhance a breeder's ability to develop breeding strategies that include the breeding of high risk pedigree dogs. Lowering inbreeding (http://www.canine-genetics.com/Price.htm ) and line breeding in these higher risk pedigree lines by out crossing (breeding to unrelated dogs) and studying Addisons watch databases (http://www.phrdatabase.com/ ) comparing them to your pedigrees. At this point, with a minimal number of Australian Labradoodle and Labradoodle offspring with Addison's to consider, pedigree research is in its infancy.
Dr. Jerold Bell writes about polygenic disease in the following article, entitled
Managing Polygenic Disease and he uses hip dysplasia as an example:
http://www.vin.com/proceedings/Proceedings.plx?CID=TUFTSBG2003&PID=5115&O=Generic. Applying Dr Bell's breeding advice to Addison's disease, breeders can follow the same strategy they employ to avoid hip dysplasia and thereby improve their risks:
Affected dogs should not be bred.
A dog with close and/or multiple Addisonian relatives should not be bred to another with similar risks.
Only very high quality dogs with close Addisonian relatives should be bred.
High risk dogs should be bred sparingly and only to those with very few
Addisonians in their lines.
Producers and offspring of Addisonians should be replaced with a lower risk offspring or parents of the same quality.
In addition to numbers of related Addisonians, breeders should consider each affected dog's age of onset, severity of onset and any extreme environmental exposure to determine different levels of risk when assessing depth and breadth of pedigree.
In order for breeders to make the safest breeding choices possible, ALL Addison's Disease must be publicly reported. For Standard Poodles, the best and most reliable method of tracking most health issues is the Poodle Health Registry, www.poodlehealthregistry.org. written by Natalie Green Tessier http://www.poodlehealthregistry.org/docs/Standard/Addison_Files/AddisonResearch_Request.pdf
As consumers you should be talking to your breeder about this issue, and breeders should be aware of current research. Health testing, awareness of the issue and selective breeding strategies are what set breeders apart, so select wisely.
What is Addison's?
Addisons is the common name for hypoadrenocorticism, or adrenal insufficiency. It is a disease with symptoms that are common to many other ailments, making diagnosis difficult and at times a process of elimination. But once Addison's is correctly diagnosed, with a ACTH test, a properly treated pet dog can live a normal, active life (http://www.addisondogs.com/ ).
The adrenal, one on each kidney, is made up of two layers, the cortex and the medulla. The outer area, or cortex, secretes corticosteroid hormones such as cortisol and aldosterone. The medulla, part of the sympathetic nervous system, secretes epinephrine (adrenaline), which is generally not affected by Addison's. written at http://www.addisondogs.com/.
Of the three types of Addisons (Primary, Secondary and Atypical) Poodles and Poodle crosses are considered by experts capable of inheriting Primary Addison's. Diagnosis is based on the ACTH "stimulation" test that measures cortisol levels before and after stimulation by an injection of artificial ACTH (adrenocorticotropic hormone). In addition to distinguish between Primary and Secondary Addison's, it's necessary to measure endogenous (natural) ACTH levels. An Addison's affected dog can show signs at any age, but most likely between the ages of 4-7 unless illness and/or medication has shortened the time period at which Addison's would eventually be expressed.
Due to its late expression, lack of DNA testing prior to the actual expression of the disease, and no DNA testing for carrier dogs, an Addison's affected or carrier breeding dog could have a normal undiagnosed breeding life without the knowledge of the breeder.
The symptoms of Addison's disease can be vague. Initially, the dog may be listless, or seem depressed. Many dogs are described as just seeming off. Lack of appetite is also an indicator. Other symptoms include gastro-intestinal problems like vomiting and diarrhea. Pain in the hindquarters, or generalized muscle weakness, such as a dog that can't jump onto the bed as he has done in the past. Shivering or muscle tremors may also be present.
These symptoms may come and go over months or years making diagnosis difficult. If the adrenals continue deteriorating, ultimately the dog will have an acute episode called an Addisonian crisis (Potassium levels elevate and disrupt normal function of the heart). Arrhythmias can result and blood pressure drops to dangerously low levels. BUN and creatinine levels, generally indicators of kidney function, are often elevated. At this point many animals are diagnosed with renal failure, as the kidneys are unable to function properly. Typically animals are given IV solutions for rehydration, which may produce an almost miraculous recovery. This too, is a great indication that the failure of the adrenals rather than of the kidneys is creating the symptoms.
Explanation and Breeding Strategies
The main goal of the Addison's Breeding Strategies below are to guide breeders to never produce any affected puppies, however until DNA testing is available no one can ensure any Poodle or Poodle cross is not a carrier and therefore will not be affected by Addisons.
We must rely on two current detection methods:
Assumed Carrier - Assumed carriers are dogs that have produced Addison's offspring. If a Labradoodle, Australian Labradoodle or Poodle has produced an Addison's offspring it is suggested that the dog no longer be bred.
Higher Risk Pedigree - Higher risk pedigrees are those that have the same pedigree lines as those dogs that are assumed carriers, and in many cases have been inbred or line bred thus increasing these higher risk pedigrees in multitude. In addition, higher risk pedigrees have assumed Addisons carriers closer in relation to the current breeding dog, i.e. parent or grandparent. Production of affected dogs should be prevented by ensuring to the best of ones ability at least one parent is not of a higher risk pedigree.
In summary, most of the Australian Labradoodle and Labradoodle breeding stock, even those with higher risk pedigrees may continue to be used for breeding, thus maintaining genetic diversity within our breed. Armed new information we can attempt to prevent breeding a puppy that will be affected with the disease as it ages.
Where do we recommend breeders go from here?
Experts recommend breeders study their pedigrees and have a full knowledge of current assumed carriers. Poodle pedigrees should be studied in relation to the Poodle Club of America Addison's database. Breeding dogs should have yearly CBC and TgAA testing via Antech NY labs or Dr. Dodds, Hemopets. If any offspring is diagnosed with this condition, notify others so that they may benefit from adjusting their own breeding strategies.
All stud dogs should be tested yearly; every breeder should require this test of studs in service. Note yearly testing cannot fully indicate if the dog is a carrier or affected but will give yearly indicators that may lead to prior or future detection.
That stated, please proceed to expert sources for updates on Addisons diagnostic testing. Dr. Jean Dodds of Hemopets (http://www.hemopet.org) and UC Davis (http://cgap.ucdavis.edu ) are currently leading the charge. Please note I am not a veterinarian, I am a dog breeder. The information provided here is a collection of published information on Addisons produced by experts in the field, links to some of those are provide. This article is NOT an attempt to provide new information (as I am not qualified to do so), but to gather current research for breeders and consumers.
Australian Labradoodle Dogs
The information contained on this site is in no way intended to replace that of proper veterinary advice, diagnosis or treatment.
It is meant to provide resource, so that we can better understand canine health related issues.