Scientists uncover clue that may lead to treatment for hered­it­ary deaf­ness in pup­pies

HELSINKI, Finland — It’s no secret dogs have a much stronger sense of hearing than their human companions. That makes it all the more distressing when a puppy starts to lose their hearing right after birth. Now, researchers from the University of Helsinki have discovered a gene defect responsible for early-onset hereditary canine hearing loss in Rottweilers. Study authors believe the breakthrough may lead to a greater understanding of deafness in all pups and even humans too.

The team focused on a specific and rare variety of hearing loss in the Rottweiler breed. Usually, hearing loss starts early in puppyhood before worsening into total deafness by the time the dog is a few months-old. Notably, some other dog breeds experience similar hearing loss issues and most of those breeds share a Rottweiler ancestry.

“We identified the variant in the LOXHD1 gene, which plays a key role in the function of the cilia of the cochlear sensory cells. While the exact mechanism of deafness is not known, variants of the same gene cause hereditary hearing loss in humans and mice as well,” says Marjo Hytönen from the University of Helsinki and the Folkhälsan Research Center in a university release.

Passing down deafness to doggie descendants

The study reveals the LOXHD1 gene defect that causes hearing loss is a recessive hereditary trait. That means that in order for a dog to develop hearing loss it must carry two copies of the defective gene, one from each parent.

“Through our collaboration partner, we had the chance to investigate the prevalence and breed specificity of the gene variant in a unique global dataset of some 800,000 dogs. No surveys of similar scope have previously been published,” adds Professor Hannes Lohi from the University of Helsinki and the Folkhälsan Research Center.

“This enhances the significance of our finding. Thanks to our gene discovery, dogs used for breeding can now be tested for the defect. This makes it possible to avoid combinations that could result in puppies who will lose their hearing,” Prof. Lohi notes.

Sure enough, many examined dogs that had inherited the gene defect indeed developed deafness. These findings may seem narrow at first consideration, but researchers say the work their doing today with dogs may help address human hearing loss in the future.

“We have observed that both previously unknown hereditary congenital hearing loss and adult-onset hearing loss occur in several dog breeds. In addition to dogs, the preliminary findings open new avenues for investigating human hereditary hearing defects,” Hytönen concludes.

The study appears in the journal Human Genetics.

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