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Home > Cats > Can Cats Have Down Syndrome? Vet-Approved Science & Info

Can Cats Have Down Syndrome? Vet-Approved Science & Info

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Dr. Luqman Javed

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Many new and experienced cat owners wonder if their pets can have Down syndrome. The answer is no, cats cannot have this condition. Down syndrome is a condition that’s only recognized in humans. However, cats can be born with neurological disorders or defects, which we explore in this article.


What Is Down Syndrome?

Down syndrome is a condition in which a person has an extra chromosome. This extra chromosome is a copy of another, and it can affect the way that the body and mind work. The effects that it can have vary considerably from one person to the next, but the physical features of those who have Down syndrome tend to be similar. Signs in humans include a low IQ (usually but not always), almond-shaped eyes that slant up, a flattened face, poor muscle tone, and loose joints. This condition is something that a person is born with and not something that can occur later in life. However, a diagnosis may take a while for some individuals.

Why Don’t Cats Have Down Syndrome?

Humans have 23 pairs of chromosomes (for a total of 46 chromosomes), and Down syndrome results from a person receiving an extra chromosome on the 21st. Cats only have 19 pairs of chromosomes, so duplication of the 21st is impossible. In fact, there is nothing even similar to Down syndrome in cat medical literature. However, cats can be born with neurological defects or conditions.


The 5 Conditions Cats Can Be Born With Instead of Down Syndrome

1. Hydrocephalus

This condition is sometimes referred to as “water on the brain.” It is caused by an excess of cerebrospinal fluid that puts pressure on a cat’s central nervous system and damages their cerebrum (forebrain). Cats with this condition show varying degrees of signs, depending on its severity. This disease is diagnosed via an ultrasound or magnetic resonance imaging. This condition can sometimes be managed and treated with medication but at other times, might require surgery.

2. Cerebellar Hypoplasia

Cerebellar hypoplasia is a condition where the cerebellum does not develop properly. It is related to feline panleukopenia in that it occurs when the mother becomes infected with the virus while pregnant. It causes the brain’s cerebellum to develop incorrectly, resulting in poor motor control, thus affecting balance and coordination, and persistent tremors.

pregnant cat outdoors
Image Credit: Inha Makeyeva, Shutterstock

3. Hydranencephaly

Another birth defect that kittens are susceptible to is the absence of a cerebrum (forebrain), also known as hydranencephaly. This is possibly a side effect of feline panleukopenia, which infects the kittens while they’re in the womb. Feline panleukopenia may go unnoticed in a healthy adult female cat during her pregnancy but may lead to birth abnormalities

4. Hepatic Encephalopathy

This neurological syndrome is caused by a liver disease. It is most often caused by blood vessel abnormalities within the liver. Under normal circumstances, a cat’s liver is responsible for metabolizing myriad toxins and other substances within the cat’s bloodstream.

Sometimes, though, cats can be born with vessel abnormalities that bypass the liver and therefore don’t enable the organ to do its job. This is also known as a portosystemic shunt. The buildup of toxins in the bloodstream can eventually lead to signs like your cat staring into space or meowing or crying for no reason and in some cases, blindness, coma, or seizures. This disease is often diagnosed by the time that a kitten is around 5 to 6 months old.

5. Congenital Deafness

Deafness in cats can be congenital and is more likely to occur in cats that have blue eyes and white fur. In such cats, the cause is often genetic, though not all white cats with blue eyes are deaf, as several genes control this trait.

In cats that are not white and blue-eyed, congenital deafness can result from toxic or viral damage to a kitten while they’re still developing within the womb.

white British Shorthair cat with blue eyes
Image Credit: Nils Jacobi, Shutterstock



Cats cannot have Down syndrome, but cats may be born with neurological defects nonetheless. Viruses, toxins, and genetics are just a few of the factors that can affect a kitten in utero and lead to the malformation of their brain and nervous system. If you feel like your cat is displaying odd behavioral signs, we recommend taking them to the vet to have them looked over to ensure that they don’t have a health issue requiring attention.

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Featured Image Credit: Natt Ya, Shutterstock

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