Plenty of health issues can affect both humans and dogs. But what about Down syndrome? The short answer is no—dogs can’t have Down syndrome. However, they can have congenital and genetic anomalies, or health problems that are present from birth. Sometimes, these can have similar symptoms to Down syndrome.
Congenital and genetic health issues can impact a dog’s health in several ways, and the outlook really depends on the specific condition. Many dogs with these health issues still live happy, healthy lives. Here’s what you need to know.
What is Down Syndrome?
Down syndrome is a genetic condition defined as the presence of a third copy of chromosome 21. Chromosomes are little threads of information at the centre of every cell in the body that give every living organism (including humans and dogs) their unique characteristics.
Chromosomes can copy themselves too much, which may affect how cells grow. This extra chromosome can be a full or partial copy. There are three types of Down syndrome:
- Trisomy 21: This affects 95% of people with Down syndrome. Each cell in the body has three copies of chromosome 21.
- Translocation Down syndrome: This is a rare form of Down syndrome which affects 3% of people with Down syndrome. The additional copy of chromosome 21 is attached to a different chromosome.
- Mosaic Down syndrome: Around 2% of people with Down syndrome have this type. Some cells have only two copies of chromosome 21, and others have three.
In the UK, the NHS states that this syndrome affects 1 in every 377 people.
What Causes Down Syndrome In Humans?
People with Down syndrome are born with an extra copy of chromosome 21. This happens by chance, although those risks increase for mothers who become pregnant in later life. Scientists haven’t identified any behavioural or environmental factors that contribute to Down syndrome.
What Are The Features Of Down Syndrome In Humans?
Down syndrome causes some characteristic physical features, including:
- Almond-shaped eyes
- A flattened, round face
- Short or stocky build
- A small nose, mouth, and ears
- A single crease across the palm
- Poor muscle tone
Down syndrome is also linked to developmental delays and medical issues, including heart defects and hearing loss. People with Down syndrome have a wide range of abilities. Some lead independent lives, while others may need more regular support and care.
The life expectancy of someone with Down syndrome is around 60 years, although this is steadily increasing thanks to advances in medicine.
Can Dogs Get Down Syndrome?
The short answer is no. “Dogs cannot have Down syndrome, as it is specifically defined in humans,” explains Dr Kathryn Dench, a holistic and integrative veterinarian and chief veterinary advisor at Paw Origins.
She explains that Down syndrome doesn’t affect dogs due to the differences between canine and human chromosomal numbers and structures. While humans have 23 sets of chromosomes, dogs have 39.
Even though dogs can’t have Down syndrome, Dr Dench adds that “dogs can exhibit congenital and genetic anomalies that might present similar symptoms to those observed in humans with Down syndrome.” And that’s why some people might think that dogs develop this condition.
Let’s take a closer look at some of those conditions.
Which Conditions Can Dogs Get That Cause Similar Effects to Down Syndrome?
Some health issues in dogs can cause symptoms like stunted growth, facial abnormalities, and developmental delays. “These conditions, while genetically distinct, can mimic the appearance or behavioural aspects associated with Down syndrome in humans,” explains Dr Dench
Congenital hypothyroidism
Low thyroid hormone levels usually cause this condition. This can be down to genetic issues, or developmental abnormalities that impact the thyroid gland.
Symptoms include:
- Stunted growth
- Delayed development
- Poor muscle tone
- Impaired cognitive function
Juvenile-onset panhypopituitarism
Juvenile-onset panhypopituitarism happens when the pituitary gland is either malformed or underdeveloped. It’s usually due to developmental defects or genetic abnormalities.
Symptoms include:
- Slow growth
- Lethargy
- Poor muscle tone
- Weight loss
Growth hormone deficiency
Growth hormone deficiency occurs when dogs don’t produce or secrete enough growth hormone. It is caused by developmental abnormalities, disorders within the pituitary gland, or genetic mutations.
Symptoms include:
- Slow growth
- Reduced muscle tone
- Small size
Portosystemic shunts
Portosystemic shunts can be congenital or develop later in a dog’s life. They occur when an abnormal blood vessel diverts blood flow away from the liver, impacting the liver’s ability to detoxify the blood and absorb nutrients correctly.
Symptoms include:
- Seizures
- Poor growth
- Gastrointestinal issues
How Can A Pet Parent Spot Signs of a Congenital Health Problem in their Dog?
If you spot any of the above symptoms in your dog, it’s a good idea to book an appointment with your vet. They’ll arrange a thorough examination to uncover what might be causing these issues.
Dr Dench explains that this exam will likely include “genetic testing and diagnostic imaging, which can help differentiate between these conditions.” She adds that “some of these symptoms, particularly behavioural or developmental aspects, can be caused by neurological infections, which is why consulting a veterinarian is so important.”
Dr Deborah Aronson, founder of Main Line Veterinary Integrative Practice, explains that some congenital anomalies may not be immediately apparent at birth, with symptoms developing over time.
“As your puppy grows, watching for general symptoms of well-being (e.g., normal energy, attitude, and body shape) and getting regular veterinary care is the best way to monitor for congenital health problems,” said Dr Aronson.
What’s The Outlook for a Dog with a Congenital Anomaly?
The term congenital anomaly is a catch-all that covers any medical issues with which a dog is born. “There are many possible congenital health problems, and each has its own symptoms, depending on what body part is affected,” explains Dr Aronson.
The type and severity of a dog’s congenital health problems will impact their long-term prognosis. However, Dr Dench notes that “with the right care and interventions, many dogs with congenital issues lead full (albeit sometimes modified) lives.” She also notes that early diagnosis and tailored management plans are essential.
How to Care for a Dog with a Congenital Anomaly
If your dog is facing health challenges from a congenital anomaly, you might be wondering how best to support them. Dr Dench recommends:
- Regular vet check-ups
- A consistent routine
- A supportive home environment
- Modifications to your home, if necessary
- Physical and mental stimulation tailored to the dog’s capabilities
Dogs with congenital health issues can also develop secondary problems. Being aware of how to manage these proactively with your vet’s advice may help.
Dr Dench also mentions the importance of nutritional management, as this can significantly impact your dog’s well-being. “For example, dogs with mobility issues may benefit from a diet formulated to support joint health,” she said. Every dog’s needs will vary, so vet guidance is essential.
The right medical and dietary support, combined with patience, love, and understanding, allows many dogs with congenital anomalies to live happy, healthy lives.