Images and videos of animals with Down syndrome have been circulating on the internet for a while now. Some even have a huge fan following on social media, expressing how adorable they are. You may have heard of Kenny the tiger and Lil Bub the cat, the felines marked with Down syndrome. But can animals have Down syndrome, too, like humans? What is a fact, and what is a myth? Let’s find out.
1. What is Down Syndrome?
Down syndrome is also called trisomy 21. Trisomy is a genetic condition where living beings are born with extra chromosomes. Chromosomes are DNA molecules that determine and carry all our genetic information, including gender, shape, size, character, etc. Humans have 23 pairs of chromosomes, making 46 in total. Half of these chromosomes are passed down from the mother, and the other half from the father. People affected by Down syndrome are subjected to abnormal cell division in which they exhibit an extra copy of chromosome 21 in the nucleus of the cells in the body.
Down syndrome is a genetic disorder affecting approximately 1 in 1000 babies. Down syndrome modifies development in babies. It leads to the characteristics seen in people with Down syndrome, such as upward-slanted eyes, flattened faces, low muscle tone, and short stature. Down syndrome may cause intellectual disabilities and digestive problems. Diseases like thyroid issues and Alzheimer’s sometimes go hand-in-hand with Down syndrome. These individuals may show all, a few, or none of the mentioned characteristics. It differs person-to-person.
2. Can Animals Have Down Syndrome?
Animals may have physical and developmental disabilities similar to those seen in humans with Down syndrome, but they cannot have the carbon copy of the genetic disorder. So animals may have genetic mutations, but they cannot have Down syndrome.
3. Why is Down Syndrome Different in Animals and Humans?
Animals and humans have different genetic attributes. Hence, the result of extra chromosome copies in humans may differ from the same in animals.
Many animals are not even known to possess chromosome 21, like cats with only 19 chromosomes. Even if the animals carry chromosome 21, the genetic information stored in those cells differs from the genetic information stored in a human chromosome. So Down syndrome in animals would look very different from human Down syndrome.
4. Down Syndrome-Like Disorders in Animals
The animals mentioned below do not have Down syndrome exactly like humans. But it can be argued that some of the effects of genetic conditions on these animals are similar to the effects of Down syndrome on humans.
4.1. Primates with Down Syndrome
Primates such as monkeys and apes are the closest genetic relatives to human beings. Humans have 46, while Chimpanzees have 48 chromosomes. Chromosome 22 for chimpanzees is similar to chromosome 21 in human beings. Chromosome abnormality, such as an extra chromosome, found in Chimpanzees may or may not have similar effects in humans.
4.1.1. Kanako the Chimpanzee
One chimpanzee, Kanako, was born in confinement at the Kumamoto Sanctuary in Japan. Her eyes were crossed. She had underdeveloped teeth, heart problems, and feeling irregularities. She became blind at the age of seven.
It was found that she had an extra copy of chromosome 22, known as trisomy 22. Trisomy 22 found in the chimp was registered as Down syndrome. Scientists declared her condition to be “analogous” to Down syndrome. They explained that her disorder had the same symptoms as those of people with Down syndrome but differed in structure.
4.2. Tigers with Down Syndrome
4.2.1. Kenny the White Tiger
Kenny was a white tiger that lived at Arkansas’ Turpentine Creek Wildlife Reserve. He was rescued in 2002 and taken care of in this facility till his death in 2008. He had genetic facial deformities such as a short snout, wide-spread eyes, and a permanently open mouth. He was an internet sensation because his physical appearance was similar to those with Down syndrome. But white tigers can’t have Down syndrome as they have 19 chromosomes.
Kenny’s condition has been blamed on hostile inbreeding practices rather than genetic mutation. White tigers are rare but in demand for their eccentric fur. They are forcefully reared through inbreeding to maintain their special white fur. In 2019, the American Zoological Association banned the inbreeding of white tigers, which was being done to increase the production of “single rare alleles.”
4.3. Cats With Down Syndrome
A genetic disorder seen in cats called Klinefelter’s Syndrome can have a common symptom with Down syndrome. It is also known as XXY syndrome. It is a sex chromosome disorder that happens when a male cat has an extra X chromosome. Klinefelter’s syndrome is another type of trisomy, like Down syndrome, related to additional chromosomes.
Cats cannot have Down syndrome because, as mentioned above, they only have 19 pairs of chromosomes rather than the 23 pairs needed to have the genetic problems associated with Down syndrome. But here are three cats that became celebrities because of their genetic abnormalities that the internet associated with Down syndrome.
4.3.1 Otto the Kitten
Otto was declared to have a Down condition by a veterinarian in Turkey. The vet determined so through Otto’s unusual facial structure. Its abnormalities could have resulted from a hormone deficiency, but people thought his early death was due to Down syndrome. The kitten had begun having seizures and died because of cardiovascular complications at 2 months of age.
4.3.2. Monty the Cat
Mikala Klein and Michael Bjorn rescued Monty from an animal shelter at three years of age. He has a chromosomal defect, not to be confused with Down syndrome, leading him to have a sunken nasal bridge. He has an odd physical expression but is much loved and popular and has a Facebook following of over 400,000 fans. Despite the short lifespan of animals with genetic conditions, fortunately, Monty is still alive today and is gracing our Instagram feeds with his gorgeous face.
4.3.3. Lil Bub the Cat
Lil Bub had many genetic mutations, which included feline dwarfism and extra toes. She couldn’t hold her tongue in her mouth because of her condition.
But that didn’t stop her from becoming mega-popular online. She was famous on Reddit, Tumblr, and Facebook and appeared in many shows, including The View and the Today show. She also has her own documentary called Lil Bub and Friendz.
Lil Bub fought an aggressive bone infection and tragically passed away on the first day of December 2019.
4.4. Dogs with Down Syndrome
Macroglossia is a disorder characterized by abnormally large tongues. Macroglossia occurs due to muscle tension and enlarged cells. A large tongue can cause it to constantly hang out of the dog’s mouth leading to a reduced range of movement and breathing difficulties. Dogs having macroglossia are often associated with Down syndrome, but that is incorrect. A dog may have an increased risk of macroglossia due to some disease or if they have an allergic reaction.
Other conditions, such as congenital hypothyroidism in dogs, may look like Down syndrome, but it is not. Similar symptoms include mental dullness, mental disabilities, and weak muscle tone. Delayed growth is also a common symptom of congenital hypothyroidism and Down syndrome.
Dogs have 39 pairs of chromosomes. Researchers haven’t been able to study each chromosome to determine which one coincides with the 21st human chromosome to find an analogous relation to Down syndrome in humans.
4.5. Giraffes with Down Syndrome
Giraffes are the tallest animals on earth. But dwarf giraffes with growth defects exist too. Their condition is not due to Down syndrome. They have a genetic mutation leading them to have skeletal dysplasia. Skeletal dysplasia causes giraffes to have bones in unusual structures in their head, arms, legs, and spine.
4.5.1. Julius the Giraffe
These giraffes may also have birth asphyxia. Birth asphyxia is when the baby giraffe has oxygen cut off in the womb and cannot develop properly. An example of this can be found in Julius, a giraffe from Maryland Zoo in Baltimore in the United States. Julius had brain and nerve damage, so his head leaned heavily to the right side, resulting in a crippled tongue.
4.6. Mice with Down Syndrome
Studies have shown that mice can have chromosomal damages where they can create extra genetic material. They can grow an additional chromosome 16, which shows similar characteristics to the symptoms of Down syndrome. But this can rarely be observed in the population of wild mice as offspring with these genetic imperfections mostly die before birth. Scientists know this knowledge because they created these genetic situations while studying laboratory mice.
Down syndrome is a disorder that affects human beings. Animals have different chromosomes than humans in number and genetic makeup. Hence, animals cannot have Down syndrome. However, they can have other related genetic abnormalities. Again not all animals may necessarily have variations of Down syndrome.
Animals with Down syndrome started as an online trend. While animals are adorable and deserve all the love in the world, creating false trends is undesirable. The animal kingdom is always subjected to a wide variety of speculations; unfortunately, they can’t speak for themselves to clear up the rumors and gossip surrounding them.