Down syndrome in dogs: everything you need to know

Updated 20/09/2023

Is Down syndrome in dogs even a thing? The simple answer is no, and we’ll explain why a little later. While vets can’t strictly diagnose your dog with Down syndrome, genetic conditions and other health issues with similar symptoms can be. So, here we explore what those are and how you can make your furry family member’s life as happy and comfortable as possible.

And if your dog has been diagnosed with genetic abnormalities or any health condition for that matter, it’s really important that you find an experienced dog sitter to keep your beloved pooch safe and healthy while you’re on vacation or away for a business trip.

What is Down syndrome?

According to OxfordLanguages, Down syndrome is a disease present from birth that’s usually caused by a defect involving chromosome 21. The most common defect to the chromosome is that an extra copy of it is present. Down syndrome is relatively easy to diagnose in humans due to the key physical characteristics that it’s associated with. These include a flattened skull, pronounced folds of skin in the eye’s inner corners, a large tongue and a short stature. It’s also likely that people with Down syndrome will have some level of limitation to their intellectual ability along with their social and practical skills. The latter varies massively though, and people with Down syndrome can need a varied level of care, while others have high levels of independence. For example, some people with Down syndrome will need regular care while others can gain employment and live a more independent life.

Can dogs have down syndrome? 

Down syndrome in dogs is not possible. In humans, Down syndrome is characterised by the additional chromosome. So, a person without Down syndrome will have 23 sets of chromosomes, so 46 in total. And a person with Down syndrome will have 47 in total due to the additional copy of chromosome 21 that we talked about earlier. Dogs on the other hand (without a genetic abnormality) will have 39 chromosome sets, so 78 altogether. And that’s why Down syndrome in dogs can’t be diagnosed, because the condition is defined by the human number of chromosomes, not dogs’. 

So, why is the question, can dogs have down syndrome, even asked in the first place? Well dogs do experience genetic abnormalities. And while those abnormalities aren’t strictly classified as Down syndrome in dogs, our four legged friends with genetic deviations do display some of the physical characteristics that a human with Down syndrome does. Dogs also suffer from a variety of health conditions with similar symptoms to Down syndrome, so pet parents can often misdiagnose.

If it’s not Down syndrome in dogs, what is it?

While we can’t strictly say that dogs can have Down syndrome as we define it in humans, they can also experience genetic abnormalities and health conditions that are similar to those in the Sapien world.

We’ll explain each of these in more detail, but first, here are some health conditions that are often confused with Down syndrome in dogs:

• Pituitary dwarfism (growth hormone deficiency)
• Congenital hydrocephalus
• Portosystemic shunt
• Congenital hypothyroidism 
• Congenital heart disease

These conditions are congenital (aka present from birth), but some of them can also develop during a dog’s lifetime for various reasons.

Pituitary dwarfism

Pituitary dwarfism in dogs is caused by deficiencies of the growth hormone that’s produced by the pituitary gland. It often occurs because of a poorly developed pituitary gland, or a pituitary gland tumor. It can be difficult to detect in newborn puppies, but in the first few months of life, the characteristics are more noticeable. Features include short legs, a long body, short jaw, bulging eyes, bacterial skin infections and baldness. The growth hormone deficiency causes underdeveloped kidneys which leads to renal failure. Growth hormone deficiency can also cause underactive thyroid glands. This can then cause restricted intellectual abilities. Dogs with pituitary dwarfism are likely to be sterile and will have a shorter life expectancy if the disease is left untreated. There are some treatments available though, so if you suspect your dog has symptoms similar to Down syndrome, then head to the vets.

Hydrocephalus

Hydrocephalus hydrocephalus is caused by excess cerebrospinal fluid (CSF) in the brain  This causes brain swelling and pressure on the brain’s tissues which can lead to permanent brain damage and death. Puppies born with the disease tend to have a dome-shaped skull, an enlarged fontanel (the soft spot), and eyes that look downwards. The defect can affect dogs from birth, but it can also be acquired from infection, tumors and swelling. Signs to look out for include head pressing (when dogs literally press their heads against the wall), loss of vision, pacing, seizures, restlessness and a lack of spirit. Dogs most likely to have congenital hydrocephalus are small, miniature and toy breeds, as well as breeds with shorter faces (brachycephalic dogs), like the Chihuahua, English Bulldog, Pekingese, Toy French Poodle, Boston Terrier, Manchester Terrier and Yorkshire Terrier.

Portosystemic shunt

Dogs with portosystemic shunt experience stunted growth,poor muscle development, disorientation, head pressing, seizures and staring into space. Some will also drink or urinate more often than normal, along with vomiting and diarrhoea. Also known as liver shunt, it occurs when a connection between the portal vein or one of its branches and another vein is made. This allows blood to bypass (or shunt) around the liver.

Congenital hypothyroidism 

It’s an underactive thyroid gland that is present in affected puppies from birth. It’s very rare, but affected pups usually have mental impairment, skeletal developmental abnormalities and dwarfism.

Congenital heart disease

Pet parents might initially suspect Down syndrome here as congenital heart disease can cause stunted growth along with other characteristics like exercise intolerance, collapse and seizures.

Symptoms of Down syndrome-like conditions in dogs

• Atypical facial features (like bulging eyes)
• Downward gaze
• An abnormally broad head
• Poor eyesight
• Hearing issues
• Short legs
• Perceived intellectual limitations
• Poor muscle tone
• Head pressing
• Disorientation
• Circling

Caring for a dog with Down syndrome-like symptoms

If your pooch has been diagnosed with a condition or disease similar to Down syndrome, first and foremost you should take advice from your vet on your pup’s specific condition. With that in mind, here are some tips on taking care of your dog with Down syndrome-like symptoms.

• Head to your vet. If your pup is displaying Down syndrome-like symptoms, head straight to your vet. While we know that dogs can’t strictly be diagnosed with Down syndrome, the symptoms they’re showing might be a sign of something serious. So, talk to your vet to get a diagnosis and make a care plan to help them live the happiest, most comfortable life they can. 
• Clear the living space and keep essential items in the same spots without moving them around. Dogs with Down syndrome-like characteristics may have poor eyesight, limited intellectual abilities and physical restrictions that make moving around more difficult for them. So, clear your living space of obstacles to make getting from A to B easier, make their living environment consistent, and see their quality of life improve.
• Vet check-ups. Whatever your dog’s condition is, it’s really important that you schedule regular checkups with your vet to make sure things aren’t getting worse, they’re on the right medication, and that you’re doing everything you can to make their quality of life the best possible.
• Quality nutrition. Speak to your vet about the right food for your dog’s condition, and make sure they’re getting the right amount of water each day to avoid under or over-drinking.
• Comfort. Having a condition similar to Down’s syndrome for dogs can make daily life a serious challenge. So, make sure they’ve got a bed that’s super comfortable and that they’ve got everything they need in close proximity to avoid straining their bodies.

Down syndrome-like symptoms in puppies

Diagnosing your dog’s condition as a puppy can be much more difficult than diagnosing Down syndrome in humans, so if you notice any of the symptoms we’ve discussed above, take your pup to the vets to get a diagnosis and an appropriate care plan.

Meet our veterinary expert, Jnanee

This article has been checked by veterinarian Jnanee Krishnasamy, BVSc (Massey). Dr Jnanee is a small animal veterinarian. She was born in sunny Singapore and spent her formative years there, before studying veterinary medicine at
Massey University. Since graduating from vet school, Dr Jnanee has worked in a variety of settings that include private practice, shelter medicine, and veterinary telemedicine. Due to her varied experiences, she is well-informed on many aspects of the veterinary industry!

Does your pup struggle with sleep?

While it can, it doesn’t always take a genetic disorder or serious health issues to make a pup struggle with settling down at night. So, if you’re wondering how to get a puppy to sleep through the night, look no further.