Simple Facts: Trisomy 21 Or Down Syndrome In Cats

Down Syndrome In Cats
Photo By Alexas_Fotos - Pixabay Copyright 2016
Does Down Syndrome In Cats Exist? – This question has been asked by veterinary experts more often than one might think. Typically, this question is asked when cats seem to look and behave abnormally, which resembles Down syndrome.

The question about a down syndrome cat was made famous by Monty the cat who was born with certain problems. He had health problems and facial structure injuries that were similar to humans who were born with Down syndrome.

Monty’s photos were posted on Instagram and it took the internet by storm. Many pet parents created accounts for their cats that showed similar signs as Monty. Additionally, they believed their cat also had feline Down syndrome.

Monty the cat is famous for his broad nose, which is a clear sign of the symptom. However, it was not known for sure whether he was born with an abnormality or developed it later because of an infection or trauma. Both of these ailments can cause facial bone abnormalities.

Certain behavioral abnormalities like unusual facial features in cats have become popular on Social media. Furthermore, people are claiming that these cats have down syndrome, hence advancing the belief that Down syndrome in cats is possible.

Cat Closeup
Photo By Francesco UngaroPexels Copyright 2019

Regardless of the rumors or doubts on the internet, cats do not develop Down syndrome and they cannot do so even in the future. Down syndrome is a disorder affecting one in seven hundred human babies born in the US each year. Also, it happens when the developing fetus’s genetic material is copied incorrectly. As a result, an extra chromosome 21 or a partial chromosome 21 is formed in this condition called trisomy 21.

Down Syndrome in Humans

In short, chromosomes are responsible for organizing the DNA into bundles in each cell. Such useful cells pass on the DNA or genetic material when they divide. However, from time to time an extra chromosome 21 or partial chromosome 21 causes a variety of birth defects resulting in people born with Down syndrome and shared physical traits.

Tri-Colored Cat
Photo By cat-observerFlickr Copyright 2013

As explained by the National Down Syndrome Society, people with this syndrome share some or all of the following traits:

  • Low muscle tone
  • Small stature
  • An upward slant to the eyes
  • A deep crease across the palm in the center

Most importantly, it is noticeable that all people with this syndrome do not look alike. In humans, Down syndrome is also known as Trisomy 21, which is a common genetic condition caused by the presence of an extra copy or partial copy of chromosome 21.

This syndrome was named after John Langdon Down, who was a British doctor in 1866 who described the syndrome in people. The parents of children born with these physical characteristics are usually genetically normal. Also, the condition is believed to occur by chance with a higher incidence in older human mothers.

In human beings, Down syndrome could cause mild to moderate mental disabilities. Along with that, it often comes with decreased muscle tone, shorter heights, and upward slanting eyes.

Why Down Syndrome in Cats Doesn’t Exist

In total, humans have 23 chromosomes whereas cats have 19. So, having an extra chromosome 21 is clearly impossible for cats. However, it does not mean cats cannot or will not have extra chromosomes occasionally.

Additionally, a 1975 paper that was published in the American Journal of Veterinary Research identified a rare chromosomal abnormality. This was discovered in male cats that allowed them to have an extra chromosome, which resulted in a condition similar to the Klinefelter syndrome of humans.

Cat with the chromosomal defect has an extra chromosome that carries genetic material affecting their coloration. Moreover, this condition causes these male cats to have a color pattern generally seen only in female cats.

Cat Walking On Ledge
Photo By Timothy MeinbergUnsplash Copyright 2017

Abnormalities that Could Resemble Down Syndrome Symptoms

Simultaneously, there may have been some particular cats on Instagram that became online sensations after their owners claimed that these cats and their unusual appearances were results of extra chromosomes. But, it is unclear whether these claims surrounding chromosomal disease have ever been verified through genuine genetic testing.

Despite the questionable biological realties and claims, feline Down syndrome has become a famous term. However, the veterinary community does not recognize such syndromes as a veterinary condition. Along with that, it does not advocate the transference of human conditions to animals on just the basis of physical appearance or behavior.

Typically, so-called Down syndrome-like symptoms typically manifest as some distinctive characteristics, such as:

  • Broad noses or squished noses
  • Widely spaced upturned eyes
  • Small or unusual ears
  • Low muscle tone
  • Difficulty walking
  • Difficulty with elimination (urination or defecation)
  • Hearing or vision loss
  • Heart problems
  • Perpetually saddened face
  • Motor dysfunction
Panleukopenia Virus:

This infection is also called feline distemper and it is rare because of the effective vaccinations. But, it can still occur in cats sometimes where the cat is infected in utero and a part of the brain called the cerebellum is severely damaged.

This virus kills cells that are rapidly growing and dividing in a developing uterus. This can also cause a lack of coordination, resulting in clumsy or unbalanced walking and other movements.

Toxic Substances:

Exposing toxic substances to the pregnant cat mother can produce a kitten with neurological problems that affect the brain and many other parts of the body.

Cerebellar hypoplasia:

Furthermore, just like the panleukopenia virus, Cerebellar hypoplasia is a congenital disorder that affects the development of the cerebellum.

Trauma to the head:

Blunt force trauma to the head can also result in intellectual impairment along with compromised balance and coordination. Not to mention facial injuries and other problems in cats.


A kitten who did not get enough nutrients including calories can have an improperly developing neurological system. Along with that, it compromises the brain and the rest of the central nervous system.

Feline dysautonomia:

Cats with this disorder can have depression and a dangerously low heart rate. The combination of these conditions could make it seems as if something is off with mental acuity.

Cats with Physical and Behavioral Abnormalities

The physical features and behavioral abnormalities of so-called “Down syndrome in cats” are telltales of some other condition, one which may not even be genetic in origin. Furthermore, the appearance and behavior of cats with such abnormalities could stem from a wide range of ailments such as congenital abnormalities, neurological diseases, infections, and even trauma.

Expectations for Special Needs Cats

Cats exhibiting such abnormalities are typically called special needs cats. Also, special needs cats display many traits that could resemble traits associated with Down syndrome, even though it is impossible for cats to develop this condition.

Specials need cats are termed as such because they need special care. Their owners must take extra care to protect them from the hazards of pools and stairs as well as predators and other dangers, which they are extremely vulnerable to. Along with that, such cats may need help doing something as basic as eating, drinking, cleaning themselves, moving around with vision or hearing loss.  

Owners with special needs cats must enlist their veterinarians as allies. Also, anyone with such cats should learn about their full range of health care options. Simultaneously, people can google cats and Down syndrome in cats and learn more about these things and their physical or behavioral features.

If anything about the pets is making their owners think of Down syndrome in cats, they must immediately take him/her to the veterinarian for a professional diagnosis. For some things, there might be a cure especially if this cat is still a developing kitten.

Furthermore, even if the main problem cannot be fixed but results in another problem then the vet may be able to prescribe medicines that keep the situation from worsening.

Moreover, a veterinarian will be able to do an X-ray scan, run genetic tests, and other specific tests needed to diagnose any serious genetic disorder or disease. There have been cases where cats have been diagnosed with a genetic disorder that is very close to so-called feline down syndrome or Down syndrome in cats.

One more thing to consider is if a cat is diagnosed with a condition requiring surgery then he/she will need special accessories. For example, if the cat underwent surgery or has a joint problem anywhere, the owner will need to be careful with his/her collar. Ask the vet for help to choose the best type of collar for the feline’s needs.


Cat Paw
Photo By Александар ЦветановићPexels Copyright 2018

Feline Down syndrome or Down syndrome in cats is not possible because of the cat’s genetic structure. However, some neurological and other genetic disorders may be responsible for similar Down syndrome symptoms.

In short, if you think that your kitty is showing any similar qualities to that particular syndrome, visit a qualified veterinary expert to get it diagnosed and treated. Should you still keep the social media account? The answer to this is YES.

People can still keep their cats’ social media accounts as it will be a great way to educate people about special needs cats, chromosomal abnormalities, motor dysfunction issues, physical abnormalities, genetic mutations, genetic defects, and permanent neurological damage.


Content is medically reviewed periodically by professionals for accuracy and relevance. Reviewers include doctors, nurses, mental health professionals, and even medical students. 


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