Animals with Down syndrome can be seen all over the internet. Some even have a fan following on social media. While many of these animals do have a chromosome disorder, they don’t actually have Down syndrome as we know it in humans. Here’s what we know about Down syndrome and how animal Down syndrome is actually a myth.

What is Down syndrome?

Down syndrome is a genetic disorder that is caused by abnormal cell division which results in an extra copy of chromosome 21. Down syndrome is also known as trisomy 21. A person with Down syndrome may have an extra or full copy of chromosome 21. Typically people are born with 23 pairs of chromosomes. Half of these chromosomes are inherited by the mother and half are inherited from the father. Chromosomes are the rood-like structures that carry all of our genes and inherited traits. With Down syndrome, the extra genetic material alters the course of development. This causes the characteristics we typically see with Down syndrome, such as small stature, an upward slant to the eyes, low muscle tone, and a flattened face. Someone with Down syndrome may have all or none of these traits. There different degrees in which someone can possess these characteristics.

Down syndrome is the most common chromosomal condition. One in every 700 babies in the United States is born with Down syndrome. That’s around 6,000 babies in the United States being born with Down syndrome. The cause of the extra partial chromosome or full chromosome is still unknown. So far, the only factor that has been linked to causing Down syndrome is maternal age. It’s still hard to say this is the cause as 80% of children with Down syndrome have mothers who are under the age of 35. This is because more women under the age of 35 are having babies. It’s also important to note that only 1% of babies born with Down syndrome have a hereditary component. A woman who is 35 has a one in 350 chance of having a baby with Down syndrome where a woman who is 45 has an increased risk of one in 30.

Down syndrome animals

Because the genetic make-up of animals is too different from that of humans, it’s almost impossible to say that duplication of chromosomes would have the same effect on an animal that it does on a human. Many animals don’t actually have chromosome 21. Cats only have 19 pairs of chromosomes, for example.

The animals you see on social media do have various chromosome disorders, hormone deficiencies, inbreeding, and other conditions that show physical traits similar to those associated with Down syndrome. There are several heartwarming cases where animals with chromosome and other disorders get adopted and this is crucial to helping them get the extra care they need. To say they have Down syndrome is completely false, however.

Apes with an extra chromosome

While it is a myth to say that animals have Down syndrome, apes are one case where there have been cases of chromosome abnormalities that are somewhat comparable to Down syndrome. Apes have 24 pairs of chromosomes. Humans have 23. There have been some apes who have been born with an extra chromosome 22 which is similar to chromosome 21 which is found in humans. According to a study conducted in 2017, a chimpanzee who had the extra chromosome experienced symptoms similar to those found in people with Down syndrome. These symptoms included growth defects and heart problems. Researchers still remain unclear about this disorder and although it was a chromosomal defect, it wasn’t Down syndrome. Despite what you may see online or on social media, there has yet to be an animal with the same form of human Down syndrome or trisomy 21.