Can Dogs Have Down Syndrome?

Reviewed By Kim •  Updated: 10/05/21 •  9 min read
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Have you ever wondered if dogs can also develop Down Syndrome, just like we humans? When it comes to Down Syndrome in dogs, scientists and doctors are still asking this question themselves. Dogs and their humans do share many of the same health conditions, but not all are completely identical.

Even though there’s no definite information, it’s clear that dogs can and do develop symptoms that are similar to Down Syndrome. First, let’s take a look at Down Syndrome.

What is Down Syndrome?

Genes are the “building blocks” of life and contain all kinds of information about your body including eye color, hair color, and much more. Down Syndrome (also known as Trisomy 21) is not some disease that’s contagious; it’s a congenital condition (birth defect) caused by a genetic mutation. The condition is caused by having an extra copy (or a partial copy) of chromosome 21. That’s why this is also known as trisomy 21.

Genes are a sequence of genetic code (DNA & RNA). The genetic code is actually carried in the chromosomes, which are part of the nucleus of each cell of the body. Humans typically have 23 pairs of chromosomes, while dogs have 39 pairs.

If a problem develops with any gene like a duplication, it can cause many types of medical issues. A genetic problem can develop from a mutation—a type of change that is not normal, but different than the original genetic coding. This permanent alteration can be good or bad; genetic mutations are sometimes beneficial, but sometimes not.

Down Syndrome is caused by such a gene mutation. Humans born with this condition have an extra chromosome and this extra copy of chromosome can affect physical features. This condition will last a person’s entire life and there’s currently no cure.

According to the CDC, approximately one in every 700 babies in the U.S. is born with Down Syndrome, which is about 6,000 babies born each year in the U.S. This is the most common chromosomal condition in newborns in the United States.

Symptoms of Down Syndrome in Humans

Down Syndrome in humans has some very specific physical and mental symptoms, including:

It’s also typical for people who have Down Syndrome to develop slower—both physically and intellectually. Cognitive impairment can be mild or severe—this varies between individuals. In addition, people with Down Syndrome may have additional medical conditions such as hearing loss, vision impairment, sleep problems (including apnea), and heart problems.

Life expectancy also varies between individuals; some people may live past 60 years, while others may have a shortened lifespan.

Animals Get Down Syndrome Too

Every animal on the planet has chromosomes, which vary from species to species. All animals can develop chromosomal defects, including dogs. However, Down Syndrome has officially been seen only in chimpanzees (our nearest relative) and in genetically engineered mice.

Down Syndrome has been seen in chimps twice; one instance was in the wild and the other was a female chimp born in captivity. The chimp born in the wild had some signs of Down Syndrome and lived to be about 24 months old. The captive chimp, Kanako, was born in Japan with the gene defect (trisomy 22) that’s similar to Down Syndrome (trisomy 21) seen in humans.

So, it is possible for other animals to develop symptoms similar to Down Syndrome. But what about dogs?

Can Dogs have Down Syndrome

As we said before, researchers and veterinarians are not completely sure (or in agreement) that dogs can develop Down Syndrome. However, dogs can develop Down Syndrome-like symptoms. It’s clear that genetic mutations can develop in dogs, but they may not develop the same trisomy 21 that humans can develop. Genetic material can cause disabilities in animals and very often dog owners do not become aware of their pup’s potential to have genetic diseases.

While dogs may develop symptoms that are similar, it’s not certain they can develop Down Syndrome like humans. This condition is just not often seen and is extremely rare in dogs. Genetic mutations in dogs can lead to early death–this may even happen before a puppy’s born. If a puppy with a genetic abnormality survives birth, he may not live long enough for symptoms to appear. The pup’s mother may sense something’s wrong with it and reject or kill the puppy. In addition, it’s rare for most puppies or dogs to undergo genetic testing, so the condition may not be diagnosed or could even be misdiagnosed during regular checkups. Some puppies may not even show symptoms or signs of this condition until they’re a year or two old. Some will be diagnosed from Thyroid problems.

Genetic Conditions that Resemble Down Syndrome in Dogs

Puppies can be born with birth defects or genetic disorders that resemble Down Syndrome. Some of the signs and symptoms of this condition are the similar in dogs and can include:

These symptoms and signs are common to some other health conditions, such as congenital hypothyroidism, pituitary problems that cause dwarfism, congenital hydrocephalus, lack of enough growth hormone and portosystemic shunt.

If your puppy or dog exhibits any of these signs or symptoms, then be sure to take him to the vet as soon as possible for a diagnosis. The diagnosis of a genetic issue in a dog may be a matter of ruling out other health conditions and understanding what is impacting this dog’s quality of life. Treatment will also depend on the diagnosis—so it may take some time for your vet to determine what’s causing these issues in your fur baby and if they are related to chromosomal abnormality or congenital heart disease.

Puppy with Down Syndrome

If the puppy survives to adulthood, you may notice that he has some irregular facial features. These may only be slight or they may be quite noticeable. You may notice his head is smaller than other dogs of the same breed and his face may appear “flat,” with eyes that slant upwards. His ears may also be misshapen and his neck a bit shorter than it should be. You may also notice is nose is warm and dry when touched. Pituitary dwarfism is often linked with poor eyesight in dogs with abnormal facial features. A normal dog typically does not have health problems like thyroid problems and pet owners lack knowledge to identify signs at an early state.

Dogs with Down Syndrome-like symptoms may also be hard of hearing. You may notice he doesn’t respond when called or react to sounds as he should. A puppy with this condition may also experience eyesight problems. You may notice cloudiness in his eyes, which could be an indication of cataracts. Some will experience bloody discharge, hair loss, random pain or issues with their rectum.

In addition, you may notice some behavioral issues in your puppy or dog. A puppy may be slow developmentally and fall behind his litters mates. For instance, he may be smaller than normal and/or not hit the normal achievements at the same age as his littermates.

You may find your puppy doesn’t eat on a regular schedule and it’s difficult (if not impossible) to potty train him. Puppies may not even be interested in playing like other puppies.

Dog Down Syndrome Shih Tzu

The dog breed known as Shih Tzu can suffer from some conditions that have symptoms similar to Down Syndrome. Many of these dogs suffer from medical issues that include chondrodysplasia and brachycephalia.

Chondrodysplasia is a genetic defect of the pup’s skeleton. In this condition, the dog’s bones are more like cartilage, rather than strong bone. This disorder typically causes a large head and chest, short front legs that are bowed and thick, and a back that’s too long. The spine’s disks are not “elastic” enough and don’t act as cushions, as they should. As a result, dogs born with this condition generally end up with joint problems as they grow up and have a tendency to develop arthritis.

Brachycephalia causes a round head, with a shorter than normal face. Shih Tzus with this condition usually have trouble breathing—you may hear your pup snorting all the time, especially when excited. In addition, your pup’s nostrils may seem too slim and appear pinched together. Some dogs also have soft palate issues, which causes noisy breathing, gagging, “coughing”, etc. With this condition, a dog’s eyes may also protrude. It’s important to note that dog breeds with short faces also experience some degree of brachycephalia and may have breathing trouble all through life.

Down Syndrome Dog Adoption

Should you adopt a dog with Down Syndrome? That’s a very difficult question to answer. Dogs with Down Syndrome-type symptoms are special needs pets that will take a lot of time, devotion and patience to care for. Not only that, but you’ll have to count on the dog needing a lot of medical care throughout his life.

Just as each human with Down Syndrome is affected differently, symptoms and their effects on the dog’s life will vary from dog to dog. Some dogs may be very disabled, while another pup may only show a slight abnormality—one that may not be very noticeable. It will be necessary to take this into account, too, when considering a dog with this condition.

Taking on a dog with these types of health issues is a life-long commitment. If you and your family are prepared to take on a dog with special needs, then adopt this very special fur angel! They need a home, too! But do understand this is a very long commitment—one that may also be expensive due to extra medical care, special treatments, etc. Even so, every fur baby deserves a home!

We hope this guide helps you to better understand conditions that can cause symptoms similar to Down Syndrome in dogs. These fur babies have special needs and will require much care, some requiring special dog food. We wish you and your special angel fur baby all the best!

Related Sources: PetMD Elite Daily Semantic Scholar

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Kim is a talented author, who loves animals especially dogs. She engaged in writing books and articles relating to animals a decade ago. Kim resides in Chicago with her husband and son. The family is the proud owner of a dog and a parrot (Jack and Lily). Kim wanted more than these two pets, but her husband put his foot down... She often visits elementary schools to talk to the kids about what she learned about pets and how they could learn from them.

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