GPCA Funded Project – Dwarfism Marker

2020 Final Report

It is my pleasure to report that there is finally a TEST for dwarfism in Great Pyrenees. After 24 years of gathering DNA, mapping genomes (a dwarf’s DNA was the 5th dog ever mapped completely in the world), and much hard work by world class researchers at the University of MN, we have a test. The technology involved in finding this DNA information has only existed for a few years and we are lucky that it was available to us.

I have obtained a grant from Good Dog that will assist with the cost of testing, targeting breeders who test multiple dogs and make those results public on OFA. More information on this will be provided shortly.

I would like to show my appreciation to all who have contributed DNA and supported this long project, to the AKC Canine Health Foundation and the GPCA Health Committee, who contributed funding for the research, to Dr. Mark Neff who initiated the DNA research, and to the team at University of Minnesota,
Katie Minor, RN, Dr. James Mickelson, and Dr. Kari Ekenstedt (Purdue University), who has piloted and completed this research and now, test. I’d also like to thank all those that trusted me with their dog’s DNA that contributed to the completion of this project.

A special thanks to Willow, my Great Pyrenees dwarf, born in 1997, who was the impetus that drove me to pursue this project for so long – Framboise Live and Let Live, CD, DD, TDI.

Here are some links:

• To test your dog at the University of MN: UMN Canine Genetics Lab  | Great Pyrenees Health Panel
• Good Dog Breeder Grant link Good Dog’s Club Partnership Program
• AKC Canine Health Foundation link: AKC Canine Health Foundation | Basis of Dwarfism in Great Pyrenees (akcchf.org)
• Poster for research from University of MN 2018 PowerPoint Presentation (umn.edu)
• Dwarfism report from 2007 – Dwarf Marker Project 1206a (PDF)
• Research from 1994 Dr. Ron Sande at University of Washington: Chondrodysplasia (PDF) (psu.edu)
• To complete a dwarfism Health Survey: Great Pyrenees Dwarfism Health Survey | College of Veterinary Medicine – University of Minnesota (umn.edu)
• Facebook page to support Great Pyrenees dwarfism: Great Pyrenees dwarfism Research and Information | Facebook

GPCA Funded Project – Dwarfism Marker 2020 Final Report 

Dwarf Health Survey 1999

Dwarf Marker Project 2007

Dwarf Marker Project 2020 Final Report 

Dwarfism in the Great Pyrenees & The Dwarf Marker Project with UC Davis School of Veterinary Medicine

Lead Contact: Peggy Watson Pyrstaf@aol.com

July 2009 – Dwarf Study Update

The research team headed by Dr. Neff at UC Davis recently reported that a sufficient sample of affected Pyrs (n=17) were investigated and all showed a deletion in the same region of the genome wide scan. This single locus with high statistical significance was not present in any of the control animals scanned. The researchers are proceeding with fine scale mapping of the region of interest. Within that region a marker has been identified that had a null allele perfectly identified with the defect. Currents efforts are underway to map the breakpoints of the deletion and identify genes that are affected by the mutation. It is likely that this mutation is specific to Great Pyrenees. It is hoped that the fine mapping of the breakpoints of the deletion will lead to the identification of the specific gene(s). If that happens, a DNA test can be developed. However, it is also possible that a specific gene(s) will not be clearly identified and more analysis will be required before specific gene(s) are identified.

Currently the source of funding for the study is intramural monies made available from the Veterinary Genetics Laboratory at UC Davis.

As they proceed with this fine mapping they continue to request samples form unaffected control animals and will certainly welcome any samples from newly identified affected Pyrs. Cheek swab samples are sufficient and instructions can be secured by clicking on the link above.

April 2007 – Dwarf Study Update

In late April, Dr. Mark Neff’s laboratory at UC Davis reported the achievement of an important milestone in understanding the genetic basis of dwarfism in Great Pyrenees. The research team had recently compared the DNA profiles of affected Pyrs (n=12) and unaffected control dogs (n=19), and they found a DNA marker that is highly correlated with the defect. Each of the affected dogs were uniform at the marker on chromosome 33, whereas none of the unaffected dogs had the same genetic signature. The probability of obtaining this result by chance is less than 0.000001 (for context, p < 0.05 is the typical threshold for a significant finding in biological research).

For the laymen among us, the result means two things. First, it supports the prediction that dwarfism in Pyrs is controlled by a single gene acting recessively (hence two copies of the mutation are needed for a dog to be affected). All affected dogs had two copies of the DNA marker. Second, the progress substantially reduces the problem of identifying the causative mutation (from 2.4 billion letters of DNA to slightly less than 2 million letters).

To identify the individual gene responsible for dwarfism, the researchers at UC Davis hope to collect additional samples from affected and unaffected dogs. Their target is DNA from an additional 10 affected dogs (to essentially double the power of the mapping approach).

Please contact Peggy Watson if you know of any dwarves or unaffected dogs from which blood or cheek swab samples can be collected. Peggy has the submission information for blood samples and has swabs for the cheek collections. You can reach her at pyrstaf@aol.com.

UC Davis is underwriting the blood collections at $15 per dog and is providing free shipping of the samples. To insure that no one will be unable to submit samples because of cost, the GPCA BOD has authorized reimbursement for costs beyond the $15 allocated by UC Davis.

With our help, the researchers have taken an exciting first step toward a DNA test that would allow us to eliminate dwarfism from the Pyr gene pool. Let’s continue to support the research by providing the much needed DNA samples. This will in turn allow the research team at UC Davis to progress the study to a successful conclusion, and ultimately ensuring the health of our dogs.

January 2007

The members of the GPCA Health Committee are pleased to announce the start of an initial project to search for a genetic marker for the cause of dwarfism in Great Pyrenees. Dr. Neff at UC Davis will be conducting the research and Peggy Watson is the GPCA contact person for this project. The HC recommended the project and funding to underwrite the collection of samples to the GPCA BOD. We are pleased to report that the motion passed the BOD unanimously.

Recent advances in genetic research allow Dr. Neff to proceed with a study based on three groups: one group of affected Pyrs (dwarves), a second group of Pyrs related to the dwarves, and a third group of non related Pyrs. Participants have been identified and contacted. More detailed information will be provided in an upcoming article that will be posted on the website and in the Bulletin.

This is an important beginning to a question that has been concerning GPCA members and breeders for many years. We hope that once a marker is found that it will lead to the development of a simple screening examination that will assist breeders in planning their litters to prevent this problem that has existed in our breed for generations.

We are quite excited about this opportunity.

Flo Laicher, HC Chairman

Please check back for detailed information.