Dogs can suffer from many human diseases, diabetes, hypertension, heart conditions and even cancer.
Those are well-documented, but many wonder whether dogs might also be affected by other conditions, like Down Syndrome.
There’s a lot of talk about pugs, in particular. Can pugs have Down Syndrome?
If you look at pugs, with their short limbs and flat faces, one might be tempted to say that they do have the characteristics typical for the human form of the disease.
However, there isn’t a clear cut answer to this question. To understand why it is so difficult to diagnose Down Syndrome in dogs, let’s have a look at what this disease is and how dogs can be screened for it.
What is Down Syndrome?
We all know what Down Syndrome looks like, but how does it appear?
Down Syndrome is a genetic disorder that can be traced to the moment of conception. Every human being has 23 pairs of chromosomes stored in the nucleus of each cell. It is these chromosomes that dictate what we look like and all the other traits we inherit from our parents.
At the time of conception, each parent ‘donates’ 23 chromosomes. These chromosomes pair up to determine our genetic make-up. It is during this process that malfunctions appear. Down Syndrome is also called trisomy 21, because it has to do with chromosome 21.
Instead of receiving one chromosome 21 from each parent, the child gets an extra chromosome 21 and this causes what we call Down Syndrome.
How is Down Syndrome screened in humans?
Doctors offer routine screening tests for Down Syndrome to pregnant women. In the first trimester, for instance, there are blood tests to look for Down, but they are not very reliable and have a high rate of false positive results.
In the second trimester, doctors recommend amniocentesis, to screen for Down and other brain or spinal cord defects. Such tests are highly recommended for women over the age of 35, who are more at risk of having a baby with Down Syndrome.
Down Syndrome can also be diagnosed at birth. Doctors perform a physical evaluation of the child and if they see tell-tale Down signs they order a karyotype blood test to look at the baby’s genetic make-up and see if they have an additional chromosome 21.
In rare cases, the baby has a mix of normal cells, some with two chromosomes 21 and some with three. This is called Mosaic Down Syndrome or Mosaicism, and the child will have less Down symptoms.
Can pregnant dogs be screened?
Female dogs don’t have doctors to monitor their pregnancy. In some cases, a dog owner might take the dog to the vet for an ultrasound to confirm the pregnancy, but other than that no other tests are performed, simply because they’re not available.
Dogs have 39 pairs of chromosomes in each cell and, so far, there aren’t any studies to determine if they can suffer a mutation similar to trisomy 21. Nobody knows exactly if dogs can have a condition similar to Down Syndrome and there’s no way of diagnosing it as experts wouldn’t even know what to look for at chromosome level.
There are companies that offer genetic profiling for dogs to screen for potential inherited diseases, but there is no test available for a canine version of Down Syndrome.
Can pugs have Down Syndrome?
Since the condition cannot be diagnosed in dogs, it is impossible to say whether a pug has Down Syndrome or not. That doesn’t mean that he doesn’t have this syndrome, but only that it is impossible to tell.
Sadly, pugs are plagued by a variety of genetic health problems.
- Luxating patella refers to the dislocation of a small bone in the knee known as the patella from the femur, and this affects the dog’s mobility
- Progressive Retinal Atrophy is characterized by the degeneration of the blood vessels in the retina, which, in the initial stage, leads to night blindness, even in young dogs. As the disease progresses, the dog will eventually become totally blind.
- Stenotic nares are a common problem in brachycephalic dogs. The nasal tissue is too soft, causing the nares, or nostrils, to collapse and close up, forcing the dog to breathe through his mouth.
- Pug Dog Encephalitis (PDE) is a genetic disease specific to this breed. PDE causes inflammation to the brain and the most common symptom are seizures. There are two types of PDE. In Slow Progressive PDE, seizures are less frequent, one every few days or weeks, and the dog is able to function normally between them. In Rapid Progressive PDE, the seizures are more frequent and leave the dog disoriented to the point that he’s barely able to stand on his legs. Medication can be used to control the disease and mitigate the effects, but there is no cure for PDE.
What physical features do Pugs have that are like Down Syndrome?
Pugs do have a lot of features that are quite similar to Down symptoms. For instance, they have a flat face, but that’s characteristic to all brachycephalic dogs and we know they were bred specifically to look like this.
It gives them a funny, almost human face which pet owners find cute. It also gives them a lot of breathing problems.
Also, pugs have short legs, and this is indeed a sign of Down in humans. Again, this trait cannot be put down to a disease that might affect some dogs of the breed as all pugs look like that.
On the other hand, there are plenty of other dog breeds with short legs and no one talks of Down Syndrome as far as they’re concerned.
How intelligent are pugs?
Physical traits aside, Down Syndrome is also associated with cognitive impairment. In humans, the disease causes mild to moderate intellectual disability and lower than average IQ.
What about pugs? Unfortunately, pugs aren’t among the brightest dogs. According to the Stanley Coren’s Dog Intelligence List, pugs belong in the fifth tier out of six. There’s a lot of debate surrounding the use of intelligence tests in dogs, but some of the facts cannot be ignored. For instance, according to Coren’s highly-acclaimed study, a bright dog learns a new command after less than 5 repetitions. With pugs, it takes 40-80 repetitions to understand and learn a new command, so they qualify as slow-learners. Is that a sign of Down Syndrome? That’s impossible to say. According to the same study, Chihuahuas, beagles, bulldogs or mastiffs are even slower.
Pug lovers say that it’s unfair to judge dogs solely on their ability to learn to obey and point out to other types of intelligence, like emotional intelligence. They argue that pugs star at that.
They also point out that a pug’s inability to learn might be caused by lower levels of oxygen to the brain, seeing that they suffer from breathing problems.
Are there any other dog breeds that might have Down Syndrome?
In most cases, pet owners come to suspect their dogs might have Down Syndrome when they realize their dog looks or behaves differently from other dogs. For instance, when a dog has short and deformed limbs or when the face seems flatter than what is normal for the breed.
Also, if a puppy appears to be developing slower than others, both physically or intellectually, this is often attributed to Down Syndrome.
Dogs that behave odd, whining or howling excessively are also believed to have some form of Down Syndrome.
Such symptoms can appear in dogs of every breed and they are probably caused by their genetic make-up.
The cost of owning a Down Syndrome pug
Whether or not their health problems might be attributed to Down Syndrome, pugs are prone to many debilitating diseases and this translates into more expensive vet bills.
Take, for instance, a pug suffering from PDE. Such a dog will need frequent trips to the vet and constant medication.
In humans, Down is often associated with heart defects, and this can also be said of pugs. However, experts point out that puppies born with severe congenital heart defects don’t make it into adulthood. Those that do will obviously require medical supervision, medication and a special diet.
There’s also a high emotional cost, as it’s hard for a pet parent to see their dog suffering from a debilitating disease.
It is impossible to say whether pugs or any other dogs truly suffer from Down Syndrome, since there aren’t any studies to confirm a chromosomal abnormality like in humans. Maybe in the future it will be possible to make such a diagnosis, but for now it can only be said that pugs have a lot of physical and intellectual traits that are quite similar to the classical Down signs observed in humans.
At the same time, it needs to be said that among humans the prevalence of this syndrome is 1 to 800 live births, whereas in pugs it appears to be a problem with the breed itself. In humans, Down Syndrome is an accident, a fluke, but pugs are inbred purposefully to conserve certain desirable traits. That’s not an accident, but rather irresponsible breeding.