Can Cats Have Down Syndrome?

If you’ve ever spent hours at a time looking at pictures of cats on the internet (admit it, we’ve all been there), you may have come across photographs of cats with supposed Down Syndrome.

Whether or not cats can have Down Syndrome is actually a surprisingly common question posed to veterinarians, particularly when a cat looks or acts a little different. 

But can cats really be born with Down Syndrome? We’re going to answer this question once and for all in this article, so keep reading!

What Is Down Syndrome?

Before we get into whether or not a cat can have Down Syndrome, we need to explain what Down Syndrome really is. 

Down Syndrome, also known as Trisomy 21, is a genetic condition that occurs when a person has an additional chromosome 21 in either some or all of their body’s cells.

This is caused by an error that occurs during the biological process of cell division. Individuals with Down Syndrome typically experience learning disabilities to some extent.

​Down Syndrome also tends to affect certain physical features such as the shape of the eyes and nose.

Can A Cat Have Down Syndrome?

Now that we have a basic understanding of Down Syndrome, let’s get down to the question you came here to ask: can a cat have Down Syndrome? 

The answer to this question is no. While humans have 23 chromosomes in their cells, cats only have 19.

​This means that it’s not possible for cats to have the extra 21st chromosome that causes Down Syndrome because they don’t have 21 chromosomes in the first place.

Feline Conditions Resembling Down Syndrome

If you’ve clicked on this article because your cat looks or behaves differently than other cats, you might be scratching your head at this point.

If cats can’t have Down Syndrome, what could be causing these differences? 

Physical features that may lead owners to believe that their cat has Down Syndrome include wide-set or upturned eyes, a broad nose, small ears, low muscle tone, hearing or vision problems, or unusual movements. 

While research has shown that these features in cats cannot be caused by Down Syndrome, there are other feline conditions that could be responsible.

Chromosomal Abnormality
Although cats can’t develop the extra chromosome 21 required to diagnose Down Syndrome, the American Journal of Veterinary Research did publish a paper in 1975 which explained that male cats can (very rarely) develop one extra chromosome. 

This genetic condition doesn’t look so much like Down Syndrome, but it does resemble Klinefelter Syndrome, which affects human males.

Male cats who have this additional chromosome will appear to have tortoiseshell coloring, which is only typically seen in female cats. 

Chromosomal abnormalities in cats, while not the same as Down Syndrome, can cause differences in the facial features.

The bridge of the nose may be missing, for example, or the eyes may have a unique slant to them.

Cerebellar Hypoplasia
Cats can develop a neurological condition called Cerebellar Hypoplasia. This is where the cerebellum is either smaller than normal or hasn’t fully developed. 

Felines with Cerebellar Hypoplasia will typically present with unusual movements, including difficulty walking and head tremors.

Panleukopenia
Panleukopenia is a highly contagious disease that is often fatal to cats. For this reason, it is recommended that cats are regularly vaccinated against panleukopenia. 

However, if a kitten is infected with the disease in utero, they may develop some of the physical and neurological symptoms that people associate with ‘Down Syndrome cats’.

Trauma
A cat with ‘abnormal’ facial features, an unusual gait, or other symptoms that people frequently confuse with Down Syndrome in cats, may have acquired these symptoms through trauma. 

Severe head trauma, for example, could impact the appearance of a cat’s eyes or the shape of the nose.

Injuries sustained through being hit by a car or falling from a great height could also leave a cat with life-long difficulties in terms of walking and moving around. 

How To Care For Differently-Abled Cats

If you think that your cat may have one of the conditions listed above, you might be wondering what you can do to care for them and ensure that they get the most out of life. 

Your first port of call should be your veterinarian.

If you suspect that your cat has a condition that is affecting their physical appearance, movements, mental functioning, or general health, you should share your concerns with your vet.

A vet will be able to conduct an exam, run any necessary tests, and come to a medically-informed conclusion.

This way, if your cat requires treatment or additional support, they will be able to receive it. 

It is important to understand that just because your cat looks different from other cats or behaves in a way that is unusual, that doesn’t mean they can’t lead a full and happy life.

For example, cats with Cerebellar Hypoplasia have a normal expected lifespan - they just need a little extra help and support.

Similarly, while cats with an additional chromosome often don’t survive to full term in the womb, if they are born safely and looked after carefully in the weeks following the birth, they can live healthy and happy lives. 

Just like people with disabilities, differently-abled cats are unique and each cat will have different care requirements.

​This is why it’s important to involve a qualified veterinarian in the care of your cat if a genetic or neurological condition is suspected.

Final Thoughts

Cats can’t have Down Syndrome because they only have 19 chromosomes as opposed to 23, so it’s not possible for them to have an extra chromosome 21. 

With that being said, cats can have different physical, neurological, or genetic conditions that can alter their features and abilities.

It’s possible (although rare) for male cats to have an additional chromosome.

​Physical trauma, Cerebellar Hypoplasia, or Panleukopenia in utero can also cause Down Syndrome-like symptoms in cats. 

If you suspect that your cat has any kind of undiagnosed medical condition, you should contact your veterinarian for advice.