Dwarfism in Great Pyrenees (Chondrodysplasia)
As some of you have read on our website, the current litter we have will be tested for dwarfism – this is NOT because we fear they have it! It is simply that their mother is a CARRIER (which means she has one of the two necessary genes) and therefore can create CARRIERS if bred to a male without these genes or produce AFFECTED puppies if bred to a male who also carries one or two copies of these genes.
None of our males are carriers (they are ‘clear’), nor other males that we have used.
Please note: those that carry two copies of the genes are affected and thereby dwarfs (they typically exhibit “obviously disproportionate, with shorter limbs, trunk, and muzzle compared to their normal littermates”*)
We are sharing the information about this congenital defect as we know that it is not well known, and the testing for it, through hard work from both the Great Pyrenees Club of America and the University of Minnesota Veterinary College, has only been available for the last two years.
We have never produced a dwarf Pyrenees, but know breeders who have. We are also breeders who feel it is important to embrace science when available in relation to dogs, and our breed in particular. This why we have now tested ALL our breeding stock, including older dogs that are no longer in the program but who may have produced puppies previously. With this testing we have been able to identify that our mentor kennel, Glenire Great Pyrenees did not carry this gene; instead we have found that when apparent it was the result of outcrosses to other kennels. We are sure our mentor Val would say she is “not surprised”! (Those of you who know Val will agree).
This testing is not very important to those who want a Pyrenees as only a pet or working dog, instead it is important for those looking to breed. Never have we bothered with “non breeding” contracts before, as our contract states the necessary requirements to take prior to breeding (age requirements and health testing requirements) and recommends reaching out to us if your are considering this. Most, with common sense, do not desire to breed their dogs. But again, we just wanted to be transparent and educational – and although this litter is not at risk of being affected, they could have a 50% chance of being carriers. So, we are taking the opportunity to clear it up before they even go to new homes.
In our particular case (Troll x Stachio), Stachio inherited the single gene from her mother (Nn), who inherited it from her father (sadly as he passed we are unable to confirm beyond this point its origin). Troll is 'clear' (NN) and thereby carries no genes for it. As such, up to 50% of their offspring (get out your Mendelian squares** folks) can be carriers. They cannot produce an affected puppy. But, should a puppy of theirs who is a carrier (Nn) be bred to a dog that is also a carrier (Nn) they have a 25% chance of creating an affected puppy. Therefore, dogs that have produced one affected puppy have a 25% chance of clear puppies, a 50% chance of carriers otherwise. This is important information to understand when you are also considering dogs that have a history of this syndrome in their family.
In conclusion, thank you for reading our “Coles notes” on Dwarfism. If this is what holds you back form considering a Pyrenees puppy, know that carriers have no detrimental effects from being a carrier – which is why they are then bred to other carriers and dwarf puppies created! There are no outward signs or negative impacts! Now we have the testing, we can easily eradicate this unfortunate congenital syndrome.
^image from the University of Minnesota website, demonstrating regular sized Pyrenees and dwarf Pyrenees. Note medial bowing of the carpal joints in the forelegs, as well as size difference.
*“Great Pyrenees Health Panel.” University of Minnesota: College of Veterinary Medicine, University of Minnesota, 2021, https://vetmed.umn.edu/research/research-labs/canine-genetics-lab/canine-genetics-testing/great-pyrenees-health-panel.
** “Mendelian Inheritance.” Wikipedia, Wikimedia Foundation, 2 Mar. 2023, https://en.wikipedia.org/wiki/Mendelian_inheritance.