Disproportionate Dwarfism In Dalmatians

Author: Rita Marie Boutot, MD

Disproportionate Dwarfism is a genetic disorder that has been known in Europe for many years. The prevalence of this defect is unknown as no laboratory testing was available until late June of 2025. Unfortunately, this disorder has not been seen in the US until the spring of 2025. Symptoms are insidious in onset. While there are similar presentations, it can vary significantly from dog to dog. It is important to be aware of this disorder especially since there is now testing available in order to avoid this tragedy.

Disproportionate Dwarfism is a genetic mutation in the PRKG2 gene found in dwarfism in Dalmatians and a few other breeds including the Dogo Argentino and Vizula breeds. It is a form of chondrodysplasia, a unique mutation from other chondrodysplastic disorders found in other breeds. Until June 2025, no DNA testing was available. Today, it is only available through the Laboklin Laboratories in Europe. While DNA labs in the US such as UC Davis, Gensol, and Embark, test for some forms of chondrodysplasia common in other breeds, these laboratories do not offer the DNA test for this particular mutation. A simple cheek swab provided by Laboklin or blood sample collected in a purple top tube containing EDTA is all that is needed for testing. The defect is passed down through autosomal recessive inheritance.

While this disorder was apparent in Europe for many years, now that bloodlines from Europe are readily available in the United States (US), it is imperative for US breeders to be aware of this issue, especially if using a foreign dog in their breeding program. On April 16, 2025, a Dalmatian litter of four males and two females was delivered to parents who were unknown to be carriers of this disorder. The dam and one male puppy have completed testing. The dam is a carrier and the puppy is affected. Testing is pending for the sire and other siblings being treated. Both the sire and dam had a common ancestor in the pedigree that was apparently used prolifically in Europe for many many litters. Breeders in Europe were aware this dog was a carrier of the gene and avoided breeding a sire and dam together if both had this common ancestor. However, it must be emphasized that this particular ancestor is NOT the only carrier of this defect. Many other breed lines have this defect. Now that testing is available it should be pursued with any foreign dogs prior to breeding.

The April 16, 2025 litter produced two males and one female with this disorder. As best as is known by this author, it is the only documented case in North America. Symptoms vary, but between three to four months of age, symptoms become apparent. All three puppies presented initially with a limp in one or both of their forelegs. Bowing of the front legs became apparent. All puppies began to self limit their activities. Other symptoms present in one male was a shortened tail and an asymmetry in one of the eyes. It has also been reported that an enlarged head and short neck has been seen in affected dogs.

Figure 1: Note the bowing of the legs and external rotation of the paws. The left eye is asymmetrical with the right eye.

The treatment for this disorder is not easy. To date, two of the three affected dogs have had initial surgery. The surgical procedure involves removing a portion of the ulnar bones and placing a fat pad from the shoulder to fill in the space. It is possible to perform surgery on both front legs at the same time as greater than 95% of weight bearing is through the radial bone, not the ulnar bone. Pain medications, antiinflammatory agents, and sedation is given post operatively. Crate confinement is essential. Once skeletal growth has been achieved, between seven to nine months of age, the puppy is reevaluated for any further surgical intervention thought appropriate.

Figure 2: Pup initially has dressings on both legs. Below are the X-rays showing the removal of a segment of the ulnar bones.

In summary, the genetic mutation is a catastrophic result when inherited. With education and testing, hopefully another litter will not have puppies affected in this tragic manner.

For further information, please feel free to contact me through email or Facebook Messenger.

Rita Marie Boutot, MD

Email: happytrailsdalmatians@gmail.com

Subject: Dwarfism

happytrailsdalmatians@gmail.com

Facebook Profile name: Marie Boutot

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