Scientists ID gene that causes Labrador Retrievers to collapse

Study links genetic mutation to exercise-induced collapse syndrome

September 29, 2008 (published)
By Jennifer Fiala

National Report — Researchers associate a newly identified gene in Labrador Retrievers with exercise-induced collapse syndrome (EIC) — a mutation that’s carried by roughly 30 percent of the world’s most popular dog breed.

The finding, published in the latest issue of Nature Genetics, comes from scientists at the University of Saskatchewan and the University of Minnesota (UMN), with help from the University of California-San Diego. According to the report, the identified mutation in DNM1, or dynamin 1 gene, causes a R256L substitution in a highly conserved region of the protein.

DNM1, which maps on chromosome 9, plays an essential role in communication between nerves in the nervous system, researchers say. EIC is manifested in the breed by muscle weakness, incoordination and life-threatening collapse after intense exercise. Death occurs in rare cases, the study says. The inherited condition often causes Labradors to lose control of their hind limbs following at least 5 minutes to 10 minutes of strenuous hunting or retrieving exercises. Up to five percent of the breed have this condition, researchers estimate.

“This is very exciting because it is the first naturally occurring mutation of this gene identified in any mammal,” says Dr. James Mickelson, UMN professor of veterinary sciences and a genetic researcher. “Its discovery could offer insight into normal as well as abnormal neurobiology in both animals and humans.”

And such insight now might be easier to attain, as the same researchers who identified the gene also submitted a patent application for a genetic test that can identify dogs as carriers. It costs $65 and is available through the University of Minnesota Veterinary Diagnostic Laboratory.

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