15/11/2025
More on NAD, the importance of genetic diversity and a cautionary tales - Do not “throw the baby out with the bath water” below.
My dogs are not perfect and I work hard to stay clear on what I want to improve with each breeding. Currently my girls and Dream have extremely low COI’s - 15 generation pedigrees yes i know about embark and that its more accurate. I also do understand why breeders line breed and the value. My game plan at the moment anyway is to continue to build diversity with each breeding. I am very grateful to have friends and mentors helping me.
From Dr. Shawna Cook Warning: long post
I'm in a unique position. I'm not a breeder, and I still consider myself as new to the AKC, MASCUSA, and purebred dogs. My expertise is in genetics, and I'm just a girl who happened to get a Miniature American Shepherd puppy 6 years ago with no idea of what it would lead to.
Working on neuroaxonal dystrophy (NAD) has led to me building so many (worldwide!) connections and learning so much about this breed and its history. This disease is caused by a novel mutation - not seen in any other breed - and hid for generations due to it being both recessive and difficult to diagnose, with a definitive diagnosis only possible with necropsy after euthanasia. With 1 in 4 dogs testing as carriers for this progressive, fatal disease, something needs to change.
Only breeding clear dogs, especially when there are so many carriers, is going to hurt the breed in a new way. With the stud books closed, we are stuck with the genetic diversity we have and we will only lose this diversity over time. Removing every carrier from breeding only expedites that loss of diversity.
I'm not just paying lip service to this either. I got Geno to show, play sports, and hopefully breed, knowing he was a carrier for NAD. His temperament and beautiful movement (in my totally biased opinion) are not something I can predict with 100% certainty in his (potential) offspring. NAD is.
Breed carriers to clears. Test all puppies. Keep the best pups regardless of NAD status.
The history of the Portuguese Water Dog tells us what happens when we throw out carriers. In 1989, a genetic test became available for a neurodegenerative disease that had a 6% carrier rate. Everyone avoided carriers, and it backfired. They ended up with their dogs going blind due to PRCD-PRA, which grew to an astonishingly high 35% carrier rate!
It's important to know that new mutations occur every generation! Each puppy you produce will have roughly 20 new mutations that neither parent had. Nearly all of these mutations are harmless; only a tiny fraction ever land in a gene and subsequently change how that gene works, causing a new disease, coat color, etc.
Seeing a new disease appear in your kennel doesn't mean you did anything wrong. It would happen to every breeder eventually.
All in all, I'm so grateful that I stumbled my way into such a supportive breed community. Having the opportunity to improve MY breed's health in my own way makes my job feel less like a job and more like an extension of this new hobby that I love.
Test, don’t eliminate. Let's work together to protect both health and diversity in this wonderful breed.
MAS NAD research study: https://movementdisorders.onlinelibrary.wiley.com/.../mds...
Cautionary tale of removing carriers from breeding in Portuguese Water Dogs:
https://www.purinaproclub.com/.../portugese-water-dog...
