Autoimmune diseases has jumped to the top of my interest list these past few days. My Bella has Autoimmune Thyroid Disease and Leigh's Alice has Sebaceous Adenitis. Both of these are autoimmune diseases. So I said to myself "Self, you need to become as familiar with Autoimmune Diseases as you have become with Orthopaedic diseases like LCP."
This quote from the attached article hit me very hard in the solar plex. I wonder if it will do the same for you:
"The immune system is governed by the Major Histocompatability Complex (MHC). This group of genes is referred to as a “complex” because they are all positioned close together on one chromosome. This positioning virtually guarantees that the genes will be inherited as a unit called a haplotype. The haplotype will be passed to offspring without the usual shuffling that occurs as genes are distributed into sperm or eggs. Every individual possesses two MHC haplotypes, one inherited from each parent."
Some of what I have learned through the readings and my conversations with Breeders include the following points:
1. Similar to Orthopaedic diseases, the genes from both the dam and the sire are responsible for an expressed autoimmune disease occurring.
2. The Popular Sire Syndrome effect enhances the possibilities for Autoimmune Diseases to run through the breeding stock of a kennel when outbreeding is rare or does not happen.
3. Like LCP, a clear test for a dog does not mean that his or her MHC haplotypes are not already 'fixed' genetically to produce an autoimmune offspring when paired with another dog, also with the same proclivity.
4. Like LCP, Breeders need to ensure that lines where Autoimmune Diseases have been expressed are not crossed with other lines with similar problems.
5. Autoimmune diseases are pervasive. The effect of an autoimmune disease on an affected animal lasts a lifetime and can be life-threatening.
Below is a wonderful read that everyone should become familiar with. It is clear, concise and easy to read and really brings together much of the research I'm working on right now. The following section sort of says it all when it comes to breeding affected animals, their parents and their siblings:
"Neither parents, siblings nor offspring of affected individuals should be bred back on the affected pedigree. Members of affected families used for breeding should be paired with mates from families free of disease. Breeding pairs should be selected that produce puppies with a lower COI than that of the parent from the autoimmune affected family. This will increase the probability of diversity in the MHC. The closer the relationship between an individual and its affected family member, the more care should be taken in mate selection as regards this kind of disease.
If an individual dog has produced multiple cases of autoimmune disease or allergies, especially in different and relatively unrelated mates, serious consideration should be given to withholding it from further breeding. Crosses that produce autoimmune disease or allergies should never be repeated.
If there is significant risk that a particular dog may develop autoimmune disease or allergy, as is the case with the siblings or offspring of one already affected, it would be wise to hold off breeding that dog until it is 3 or 4 years old to be reasonably assured it will not develop disease."
What is very clear to me is that retiring a dog or a bitch doesn't make the problem go away. Because the problem lies on both sides of the pedigree, it is a gift that just keeps on giving through every offspring the dam and sire have produced when they are paired with another dam or sire with the same propensity for an autoimmune disease. In particular, a popular sire has the ability to extended the critical autoimmune MHC haplotypes like greased lightning.
The most dangerous thing of all is that you cannot see, in most cases (not Alice's with her SA) an autoimmune disease developing, like Bella's Autoimmune Thyroid disease. Only tests tell you that a dog is positive for the disease. Further, an autoimmune disease can be pervasive and incrementally destructive as the animal ages.