The study by researchers at Michigan State University identifies the exact genetic mutation that leads to albinism in Doberman pinschers, a discovery that has eluded veterinarians and dog breeders until now. Interestingly, the same mutated gene that causes albinism in this dog breed is also associated with a form of albinism in humans.
"What we found was a gene mutation that results in a missing protein necessary for cells to be pigmented," study co-author Paige Winkler, a doctoral student in the College of Veterinary Medicine at Michigan State University in East Lansing, Michigan, said in a statement.
Winkler said the gene mutation found in Doberman pinschers is responsible for a condition known as oculocutaneous albinism, which also affects humans. The condition expresses certain characteristics in both humans and dogs.
"With an albino Doberman, you see a white or lighter-colored coat, pink noses and lips, along with pale irises in the eyes," Winkler said. "These traits are very similar to the characteristics humans display with this particular condition, causing light-pigmented skin and hair, along with eye discoloration and vision disturbances."
Just as people with this type of albinism experience skin sensitivity to sunlight, which can result in an increased vulnerability to skin tumors, canines with the mutated gene were also found to be at higher risk for developing skin tumors, the researchers said.
"We knew that albino Dobermans typically developed these types of tumors, much like [albino] humans, but we wondered what the actual increase in prevalence was between a 'white' dog and a regular-colored Doberman," said Joshua Bartoe, an assistant professor in the Department of Small Animal Clinical Sciences at Michigan State University, who co-led the study. "What we found was a significant increase in risk for development of melanoma-like tumors in the albino dogs."
These findings were based on a study of 40 Dobermans pinschers - 20 albino dogs and 20 "regular-colored" dogs. The researchers found that more than half of the albino dogs had at least one tumor, while only one of the regular-colored dogs had a tumor.
Bartoe and Winkler said their study could serve as a valuable resource for Doberman breeders around the world, particularly because the American Kennel Club, a registry of purebred dog pedigrees in the United States, doesn't allow the registration of albino dogs.
"Because Dobermans can carry the defective gene, but show no signs of the [condition], this has posed serious problems among breeders," Bartoe said. "But now that we've identified the mutation, we can look at the genetic makeup of these dogs and determine if they might be carriers."
The results of the new study were published March 19 in the journal PLOS ONE.