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Down Syndrome Dog: What to Expect & More | BetterVet

If you are worried that you might have a dog with Down Syndrome, or you just want to know more about whether the condition exists in dogs, look no further. This article aims to answer all of your questions about Down Syndrome in dogs, from whether it truly exists, to how you can support your dog if they show some of the characteristics.


What is Down Syndrome?


Down Syndrome is a genetic condition in humans. Most people have 23 pairs of chromosomes within the nucleus of their cells. These chromosomes store the genetic material which translates into physical traits like gender and height, as well as personality and intellectual traits. Of course, not all of our characteristics are inherited, or related to our genetic makeup; our upbringing and environment also help make us who we are. 


People with Down Syndrome have an extra chromosome 21, which might be a full chromosome or just partial. This leads to some characteristic physical and intellectual attributes which many people associate with Down Syndrome. However, not every person with this extra chromosomal material will be affected in the same way. Some can live a nearly normal life, while others are more severely impacted. Some of the traits associated with Down Syndrome include a flatter face with a less prominent nose, a shorter neck, a larger or protruding tongue, and small ears.


Can Dogs Have Down Syndrome?


Although dogs are undeniably part of the family and we often tend to think of them as humans, the truth is they’re quite different. This fact is crucial in understanding why dogs can’t have Down Syndrome. Dogs don’t have the same number of chromosomes as humans, so some extra genetic material in the form of chromosome 21 wouldn’t code for the same characteristics as recognized in Down Syndrome in people. However, it is possible that they can have extra chromosomes and they can certainly have genetic conditions. The thing is, that dogs with more serious genetic conditions involving extra chromosomes are less likely to be viable and may not survive.


While dogs can't have Down Syndrome, they sometimes display traits or characteristics that are similar to some humans with the condition, including stunted or slow growth, a flatter face, a protruding tongue, reduced cognitive function, or delayed cognitive development.


Health Conditions That Can Seem Like Down Syndrome in Dogs


None of the following conditions are actually Down Syndrome in dogs, because dogs have 39 pairs of chromosomes, compared to humans who have 23 pairs. However, these conditions may cause some similar traits for other reasons.


Pituitary Dwarfism


Pituitary Dwarfism and other conditions caused by growth hormone deficiency can cause stunted growth. Pituitary Dwarfism is caused by a genetic mutation. This can mean that physical development is slow and affected dogs will be shorter and smaller in size. Sadly, dogs with Pituitary Dwarfism are usually life limited.


Congenital Hypothyroidism


Congenital Hypothyroidism is a developmental insufficiency in thyroid hormone and can also lead to a small stature and stunted growth. However, as well as affecting a pup’s size, it can also cause them to have a longer or more prominent tongue and shorter legs. Aside from physical appearance, Congenital Hypothyroidism can also affect brain development, leading to reduced or delayed cognitive function.




Brachycephaly is the medical term for the conformation of short-nosed breeds like Pugs, English Bulldogs, French Bulldogs, and Boxers. Ongoing irresponsible breeding has led to these dogs' faces becoming flatter and their airways compromised. Because of their flatter muzzle, their tongues also tend to protrude. Of course, this appearance is very extreme, and not necessarily comparable with the more subtle flatter face or prominent tongue that someone with Down Syndrome may have.




Hydrocephalus is a congenital condition where fluid builds up within the brain. It causes affected dogs' heads to be dome-shaped, and their brain function may also be compromised.


Portosystemic Shunt


Dogs with a Portosystemic Shunt are born with abnormal blood vessels between their liver and intestine. This causes toxic ammonia to circulate in the bloodstream and can lead to neurological signs like head pressing, circling, and even seizures. Dogs with Portosystemic Shunts also have slow growth and may seem like the ‘runt’ of the litter. If your dog is displaying neurological symptoms, it is always a good idea to schedule a neurological assessment with one of our veterinarians. On the other hand, if your four-legged friend is a cat, you may want to research liver disease in cats.


When to Speak to a Veterinarian


Although dogs can’t have Down Syndrome, they can sometimes have signs or traits that seem similar. It’s important to get advice if you think something’s not quite right with your pup. If you are concerned that your dog is developing slowly, either physically or intellectually, you should  contact your Better Vet team.




Although it’s easy to think of dogs as human children or companions, genetically they're very different. That means they can't have Down Syndrome, because they don't have the same genetic makeup as us. However, that doesn't mean they can't have other congenital and developmental abnormalities that might look similar. Therefore, it’s important to monitor your pup’s development and contact your vet if you’re worried.




How can you tell if your dog has Down Syndrome?


Dogs can’t have Down Syndrome, because they have a different number of chromosomes. However, other conditions can cause some similar characteristics or signs.


How long do Down Syndrome dogs live?


Although dogs don’t get Down Syndrome, they can have other conditions that affect their physical appearance and cognitive development. Many of these conditions affect their life expectancy, but this depends on their diagnosis.


How do you care for a Down Syndrome dog?


Dogs can't have Down Syndrome, but if you have a dog with any abnormal signs you should contact your veterinarian. They will be able to help you support them and ensure a good quality of life where possible.