How to Tell if Your Dog Has Down Syndrome

Can a Dog Get Down Syndrome?

It is easy to recognize and diagnose Down Syndrome in humans. But what about in dogs?

Humans and dogs are different species, and as different species, we may have many similarities genetically but we also have certain distinct genetic differences. For instance, the set of chromosomes [1] in humans is 23, while dogs have 39. It means that the duplication of chromosome 21 would have different effects. 

People with Down Syndrome is categorized by 47 chromosome, including the 23 pairs of chromosomes and extra copy (full or partial copy) of chromosome 21. This extra genetic material causes the physical features and developmental changes of Down Syndrome.

It means that by default, dogs have 78 chromosomes making it impossible to diagnose them. Down Syndrome in dogs is not common but the chromosomal abnormality lead to early death in dogs. 

This is perhaps because the genetic testing needed to identify the condition is not done, and is believed not to exist. Dogs may also experience genetic abnormalities which may manifest in symptoms and some medical issues that resemble those of Down syndrome in humans.

Therefore, there is really no easy answer to the question, “Can dogs have Down Syndrome?” In canines, there are no cases like that. Even if it would occur, there is no way of knowing how it would affect them.

Many have speculated that tigers, apes, canines, and other animals can have clusters of genetic defects that at least similar to Down syndrome. The only official case of Down Syndrome was seen in chimpanzees (humans' nearest relative) and genetically engineered mice.

Scientists did experiments and genetically engineered mice to have an extra chromosome. They carried out the same physical effects in mice as can be observed in humans Down syndrome.

This chromosomal abnormality occurs in about one in 700 babies in people, but it’s even rarer in canines. For dogs, there simply weren't any recorded cases of genetic mutations or effects that would affect canines as they affect people due to the following reasons:

• It simply doesn’t exist.
• Such genetic abnormalities cause early death in a puppy.
• There is no genetic testing that could identify dogs with the canine version of Down syndrome.

All of these theories are yet to be proven or disproven. For the meantime, all of us are open to using whichever definition we believe to be most likely.

Down Syndrome-like Symptoms in Dogs

Dogs with Down Syndrome exhibit very unusual behaviors and dog owners usually don't understand these behaviors.

If you notice your dog displaying Down Syndrome-like symptoms, it is essential that you have him checked by a vet. These are some of the more obvious symptoms of Down Syndrome in dogs and other health issues to look out for:

• Abnormal facial features – Dogs with Down Syndrome have dwarf like features including a broad head, short neck,  upwardly slanting ears and eyes, small chin but large tongue, and a flattened face.
• Hearing loss – Although Down syndrome is hard to notice in dogs, you will see that your dog is too slow to follow or react to commands.
• Eye problems – Dogs with Down Syndrome may be at risk of developing a cataract in one of the eyes. Pet parents should look out for cloudiness in the eyes. If you notice cloudiness, it may indicate the formation of a cataract.
• Bloody Discharge – Your dog may have other conditions causing him to have a bloody discharge from the rectum.
• Behavioral issues – If your dog is suffering from Down syndrome, he may show certain odd traits such as shaking, howling, wailing, or whining and may also have challenges with tooth eruption. He may also be difficult to feed and tend to have a hard time controlling his bladder. Do note that some dogs struggling from difficult health issues could become aggressive. Keeping a close eye on his body language is vital in this scenario. If this behavior becomes worse, take your dog to your vet immediately.
• Random pain – Dogs with Down Syndrome have abnormally developed internal organs and some body parts can be affected.

• Developmental/mental/ growth delays– If your dog is suffering from cognitive delays, delayed tooth eruption, or slow growth eventually resulting in small stature, there could be a number of underlying health issues behind them.
• Poor muscle tone and loose joints

Are There Other Conditions that Resembles Down Syndrome in Dogs?

While a genetic abnormality is possible, dogs with Down Syndrome may also have other health conditions including:

• Congenital heart disease – Heart defects are common because in such cases, your dog has an abnormal circulatory system.
• Congenital Hypothyroidism –  Your dog may have a malfunctioning thyroid leading to poor metabolism. Congenital hypothyroidism, which is similar to Down Syndrome, is caused by low or absent levels of thyroid hormone at birth and at early in life. Down Syndrome in dogs  may have a lower temperature compared to other dog breeds.
• Pituitary Dwarfism-This autosomal disorder is caused by a growth hormone deficiency. In addition to a small physical stature, dogs like German Shepherds and other wolf hybrid breeds with pituitary dwarfism suffer from a host of health conditions including kidney failure. 
• Congenital Hydrocephalus– This is a condition where cerebrospinal fluid builds up in a dog’s skull, putting pressure on its brain. Clinical signs associated with congenital hydrocephalus include spastic or abnormal walking, changes in behavior, and failure to potty train or learn basic commands.
• Portosystemic Shunt–Portosystemic shunt is an abnormal vessel that allows blood from the intestine of the animal to bypass the liver and lead to liver failure.
• Growth Hormone Deficiency

All of which could cause symptoms similar to Down syndrome. Again, the best course you can do for your furry pal if he's displaying symptoms similar to Down syndrome or exhibiting the same health conditions is to get him to your vet for a proper diagnosis.