Google “cats and Down syndrome” and loads of entries will come up: “cats with Down syndrome for sale,” “cats with Down syndrome for adoption,” “cats with Down syndrome pictures,” and so on. But the truth is, while a cat may have physical or behavioral features that make it seem like he has Down syndrome, it’s not biologically possible.
Consider that people have two copies of each chromosome, making for 23 pairs. But someone who has Down syndrome has a third copy of chromosome 21. That’s what causes all the problems associated with the abnormality: learning difficulties, heart defects, short stature, widely spaced and upturned eyes, lack of coordination, and other issues. Cats don’t have a chromosome 21 because they have only 19 pairs of chromosomes, making Down syndrome an impossibility.
Yet some cats seem for all the world like they are afflicted with the condition. Their eyes look somehow crossed, far apart, or otherwise misaligned, or they may seem clumsy while walking, as if they have motor dysfunction issues. Others will have a squished in or broad nose, low muscle tone, or behaviors that just seem to make them lag behind other cats. If it’s not Down syndrome, what is it?
Feline issues that seem like Down syndrome
A cat could have any one of a number of problems that can seem like Down syndrome. Among them:
Panleukopenia virus. This virus, also called feline distemper, is rare because of the use of effective vaccines, but it does sometimes occur. If a cat is infected with the virus in utero, a part of its brain called the cerebellum can be severely damaged. (The virus kills cells that are rapidly growing and dividing in a developing uterus.) That causes a lack of coordination, resulting in clumsy or unbalanced walking and other movements.
Exposure to toxic substances by the mother while pregnant. This can produce kittens with neurological abnormalities that affect the brain and other parts of the body.
Cerebellar hypoplasia. Like the panleukopenia virus, this congenital disorder affects the development of the cerebellum.
Trauma to the head. Blunt head trauma can result in intellectual impairment as well as compromised balance and coordination, not to mention facial injuries.
Malnutrition. A kitten who is not getting enough nutrients, including calories, may have an improperly developing neurological system that compromises his brain and the rest of his central nervous system.
Feline dysautonomia. A cat with this disorder may have a dangerously slow heart rate coupled with depression, and the combination could make it seem as if something is off with mental acuity.
If you suspect something’s wrong
If something about your cat is making you think of Down syndrome, you should definitely take him to the veterinarian for a professional diagnosis. There might be a cure, especially if the cat is still a developing kitten. And sometimes, even if the root problem cannot be fixed but results in, say, compromised heart functioning, the vet may be able to prescribe medicines that keep the situation from worsening.
Just knowing what the issue is — even if it’s a congenital problem that can’t be worked around — is good because it keeps you from remaining confused about your pet’s condition. It will also help you relax about your cat and just enjoy him for who he is. After all, it’s not like he needs to understand nuclear physics or become an Olympic athlete. What he needs is the love and support you’re going to give him throughout his life no matter what his intellectual, medical, or physical challenges.