Neurological disorder in golden retriever dogs caused by a mutation in mitochondrial DNA

Sensory ataxic neuropathy (SAN) is a recently identified neurological disorder in Golden Retriever dogs with onset during puppyhood. Affected dogs move in an uncoordinated manner and have sensory deficits. Researchers from the Swedish University of Agricultural Sciences, Uppsala University and the Karolinska Institutet have now revealed that SAN is caused by a mutation in mitochondrial DNA. The study is published May 29 in the open-access journal PLoS Genetics.

The researchers were able to trace back all affected offspring on the maternal side, over more than 10 generations, to a female that lived during the 1970s. This implied a maternal inheritance, which was confirmed by the identification of a one base pair deletion in the mitochondrial tRNA-Tyr gene. Further analyses revealed that the mutation leads to mitochondrial dysfunction, which in turn causes a progressive loss of neurons.

The researchers showed that about five percent of the current Swedish Golden Retriever population carries the mutation causing SAN. The identification of the mutation now allows genetic screening tests to identify carriers and prevent the mutation being transmitted to further generations.

"This is a good example of how a close collaboration between clinicians and geneticists led to a rapid detection of a harmful mutation that can now be eliminated from this dog population to reduce suffering and disease," said co-author Karin Hultin Jäderlund. The study also provides a new animal model for similar mitochondrial disorders in humans, said co-author Izabella Baranowska, and could potentially be used for testing therapeutic approaches.

FINANCIAL DISCLOSURE: This work was supported by grants from the Swedish Foundation for Strategic Research, The Swedish Research Council for Environment, Agricultural Sciences, and Spatial Planning, Agria Insurance Company, Sweden, Funds of the Karolinska Institutet, the Golden Retriever Club of Sweden and the Swedish Kennel Club. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

COMPETING INTERESTS: The authors have declared that no competing interests exist.

CITATION: Baranowska I, Jäderlund KH, Nennesmo I, Holmqvist E, Heidrich N, et al. (2009) Sensory Ataxic Neuropathy in Golden Retriever Dogs Is Caused by a Deletion in the Mitochondrial tRNATyr Gene. PLoS Genet 5(5): e1000499. doi:10.1371/journal.pgen.1000499

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CONTACT:
Leif Andersson
Department of Animal Breeding and Genetics
Swedish University of Agricultural Sciences
Uppsala
Sweden
Phone: +46-18-471-4904
Email: leif.andersson@imbim.uu.se

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