Monday, October 1, 2018

Dwarfs, Miniatures, and Maxwell, Oh My!

 The recent addition of Max (now known as Maxwell Strong) to our SEVA GRREAT family makes the subject of dwarfism and miniatures a timely topic for a blog post. Some of you may be wondering why being a dwarf is a concern. Other dwarf dogs have been around for decades, some dogs are bred intentionally for those characteristics (Dachshunds and Corgis, for example), so why all the worry about a dwarf golden retriever? I would bet that many golden retriever owners have wished, if only just once, that there could be a smaller version of their beloved breed. How convenient it would be if we could sweep them up in our arms to get them out of harm’s way, help them down stairs when they are older, or maybe have enough room in the RV for a human occupant in addition to the golden retriever (or is that just my problem?). Some famous dogs have been dwarfs, for example, the much beloved Smiley who warmed hearts around the world for years.  Some breeders now produce “Miniature Golden Retrievers.” What a deal. Or is it? So with Maxwell being a focal point of our SEVA GRREAT family, it’s a good time to take a closer look at “Miniature Golden Retrievers” and also the medical condition known as dwarfism and the differences between the two.

Miniature Golden Retrievers (also known by some Trademarked names) are not small golden retrievers but are an intentional crossbreed for the purposes of producing a smaller dog with at least some golden retriever characteristics. The label “miniature golden retriever” may be applied to any mix of golden retriever with any smaller dog for the purpose of producing a dog that is smaller than the golden retriever breed standard but still has some characteristics of a golden retriever.  Most commonly this is done by breeding a golden retriever with either a small golden doodle, cocker spaniel, or poodle.  The result, in terms of size, temperament, energy level, and other characteristics, is variable depending on which breed and characteristics are most highly represented in the offspring.  Some will look and act more golden, some more cocker or poodle.  There is a misconception that such crossbreeds are healthier, a belief that overlooks the fact that many dogs share common genetic predispositions.  The same rigor in screening for health risks should be involved for crossbreeds as for purebreds.  

The term dwarfism is used with an array of unique growth patterns.  Note that being a "miniature" and being a "dwarf" dog are not related in any way.  Sometimes dwarfism involves only small stature and may even be an intentional genetic mutation as is the case with Dachsunds and Corgis. We know, however, that dogs bred for such characteristics often have significant skeletal problems and other health challenges.  There are other types of dwarfism that involve a variety of serious health concerns in addition to the small stature. Our guy Maxwell has a particularly dangerous form that poses a severe threat to his health, a form known as pituitary dwarfism. This is a genetic condition that occurs when both the male and female used in breeding are carriers, though they do not need to be dwarfs themselves.  Max's pituitary gland is not producing the growth hormone needed for him to grow and be healthy. This is not just a problem for bone growth but affects all the tissues in the body. Growth hormone is essential for life; many of the cells in our bodies are constantly growing and being replaced and, without growth hormone, those cells gradually die. It is as if Max's development arrested at a very young age. He has not produced adult teeth, still has his puppy fur, and is about the size of a 4 month old in spite of his age of 6 months. In addition, without growth hormone, as cells in the body die, they cannot be replaced which leads to progressive decline.

Pituitary dwarfism is quite rare.  The German Shepherd Dog (GSD) community is most familiar with this condition and one estimate is that as many as 30% of GSDs are carriers of this genetic mutation. Most of the research has been focused on development of screening tests to avoid breeding GSDs with this recessive trait. As Maxwell's situation makes us wonder, the incidence could be on the rise and it is showing up in more breeds beyond the original limited array of dogs.  Researchers have identified the gene mutation responsible for this condition in GSD, but it is not known whether the same genes are involved in other affected breeds. Little is known, also, about treatment and long term outcomes as the majority of these dogs are euthanized. This may not be necessary, however. There is treatment available in the form of medication to stimulate the release of growth hormone from other tissues in the body since the pituitary is not working. Although this is not the same as what the pituitary would produce if it were working properly, there are limited studies showing that after a few years of treatment the dogs did grow, achieved a normal coat of fur, and improved in a number of ways although they did remain smaller than normal for the breed. Dogs with malfunctioning pituitary glands often have inadequate amounts of other hormones produced by the pituitary, so supplementation of those may be needed as well over time, particularly hormones affecting the thyroid and the kidneys.  

Maxwell’s case seemed like a good time to write an entry on this unusual topic and also one I never expected to write. I hope people reading this find this helpful not only in understanding this beautiful little guy's challenges but also the emergence of "miniature golden retrievers." If you find yourself wishing for a small golden, be aware that small may involve other changes or possibly health challenges beyond just being a bit on the petite side.

Visit Max's Go Fund Me page for more information or if you can help support his treatment.