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Mucinosis – Why Some Dogs Wrinkle


Shar Peis originated in China about 2,000 years ago during the Han dynasty and were originally bred as fighting dogs and palace guard dogs. When Mao Tse-tung came to power in 1947, he ordered all dogs in the country to be slaughtered and fed to the poor.  It’s said that two men from Hong Kong smuggled six pairs out of the country in the early 1970’s and the breed was rejuvenated in the United States.

These dogs are a rare breed with only 15,000 known to exist worldwide today and valued between $1000 and $2500 dollars. What makes them so valuable? It’s their wrinkles. Suddenly, a genetic mutation becomes a cute factor, and much sought after feature for those looking for something different.   

Unlike people, Shar Peis are born with wrinkles and lose them as they get older because they literally grow into their skin. The obvious question is what makes them wrinkled?

Genetic Condition

It’s a condition called mucinosis. In 2008 researchers from the Universitat Autonoma de Barcelona determined that their thickened and wrinkled skin was caused by the excessive production of hyaluronic acid by the hyaluronan synthase 2 (HAS2) gene located on chromosome 13.  Hyaluronan lubricates the animals’ joints.

Of course, I knew that!  

They also have a high prevalence of a periodic fever disorder similar to human inherited auto inflammatory periodic fever syndromes.  Hyaluronan may create a “danger” signal to the immune system, analogous to the effects a pathogen may have.   

Say what?

In other words, dogs with multiple mutations of the HAS2 gene seem to be predisposed to short (12-36 hrs), but intense fevers (104-106 degrees) that cause inflammation similarly associated with auto immune diseases in human beings – like Familial Mediterranean Fever. This disorder causes inflammation of the abdomen and chest in people of Mediterranean and Middle Eastern descent.  

Shar Pies respond quickly to anti-inflammatory drugs, but the prolonged fevers can injure their kidneys.  Human periodic fever disorders are very similar in nature.  

Human Disorders & Aging Process

Finding that hyaluronan is a major trigger of fever opens a new research field in canine and human inflammatory disease,” said senior author Kerstin Lindblad-Toh, a professor in comparative genomics at Uppsala University in Sweden. Knowing this, breeders can now design reproduction programs aimed at improving the health of these animals without mutant duplications.  

Most Wrinkled Dog Breeds

Other wrinkled dog breeds include:  English Bulldog, Dogue de Bordeaux, Mastiff, and Pug. Most of these are brachycephalic (short head and flat face) breeds.

Other animals include the Meishan pig. Originating in China, they are a small farm pig known for their wrinkled faces and long droopy ears. The genetic basis for their look is unknown and is not a deliberately produced trait. Researchers are now investigating breeding Meishans with regular pigs used in large commercial farms because of the advantage that they can breed at a younger age and produce bigger litters.  

In Merino sheep breed called “A Type”, they carry extra wool because of extra skin that produces deep wrinkles, especially around the neck.  

Side Effects

While wrinkling can contribute to the appeal of a breed of domestic animal - when taken to the extreme it tends to lead to disease and infectious risks and be detrimental to the welfare of the animal. So, when choosing designer type breeds, it’s important to know the conditional side-effects.   

  • Infection-causing bacteria and dermatitis.

  • Entropion – a condition whereby the heavy skin on a Shar Pei’s head forces its eyelids to turn in causing their eyelashes to scratch their cornea, leading to blindness.  

  • Some owners are dumping these animals at alarming rates when they discover they have to fork out at least $2000 for corrective surgery.   Amazingly, a retired Melbourne grandmother Amanda Booth is using her life savings to pay $15,000 a year to rescue and re-home as many of these dumped dogs as possible.

  • People are petitioning new laws to breed out dogs whose litters require entropion surgery.

  • In Australia, Shar Peis are forced to have plastic surgery to save their sight.  

  • Psychological

Kermit the Frog said “it’s not easy being green” and Shar Peis being so different can’t always relate to other dogs.  That’s why Tracie Castellanos of Miami, Florida took her Shar-Pei Kuantai to a canine beauty pageant where every dog in the show had wrinkles.  “We’re searching for a wrinkly mate for him.  He’s so happy to see other dogs with wrinkles,” she said. “  

Why didn’t I ever think of that.  It’s for dogs.  I might have to try that.

Plastic Surgery

Sometimes it takes more than just face cream to fix a problem. Today, it’s not uncommon for roly-poly designer dogs to undergo radical facelifts to remove their deliberately bred folds of floppy flesh.  In this case, it’s not for vanity – it’s a life saving measure.  

That’s a little scary but medical science is pretty amazing.