Dogged genetics research identifies genes associated with skin disorder

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CLEMSON — With patches of exposed skin, large lesions across her face and dull, expressionless eyes, you might think Lorelei, a Shetland sheepdog, has been abused. But that would be far from the truth: Lorelei is loved and well cared-for. She suffers from a painful condition called dermatomyositis, a genetic skin disorder that affects dogs and humans.
Lorelei, a Shetland sheepdog living in France, became the poster dog for dermatomyositis. The disease caused painful lesions on her face, feet, ears and tail when she was a puppy, as seen in this photo.
The discovery, by Leigh Anne Clark, an associate professor of genetics at Clemson University, and her colleagues, could improve the future for dogs with dermatomyositis. The findings could also give scientists clues into the genetic variations of the 10 in 1 million people who have the disease.
“The results from our study can be used as a tool for dog breeders to prevent the disease from affecting puppies, while preserving desirable traits and genetic variation within the breed. Using this new resource, even a dog with dermatomysitis can produce healthy puppies with a mate having a compatible genotype,” said Clark.
Before their latest study, Clark and her colleagues were aware of several factors that indicated the disease is multifactorial, deriving from a combination of genetic and environmental effects.
Clark is developing a genetic test for breeders that will tell them the risk of a dame and a sire having puppies with dermatomyositis.
In dogs, dermatomyositis is seen almost exclusively in collie and Shetland breeds. A hereditary disorder will only affect certain breeds, whereas a non-genetic disorder should affect all dog breeds at the same frequency, so Clark knew the disease had a genetic basis.
Her team also recognized that the condition is a complex disorder involving several genetic components as opposed to a simple dominant or recessive disorder because of a ...

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