Are there animals with Down syndrome?

Down syndrome is a disease that exclusively affects the human race, because the chromosomal system of human beings is different from that of most animals. However, each species has certain genetic information with a specific sequence, which could cause developmental delay.

Animals with Down syndrome don’t really exist. However, they can present trisomy in another pair of chromosomes. For example, mice have trisomy when they are affected in pair number 16. In this case, the genetic abnormality can cause symptoms very similar to those in humans, such as malformations, cognitive delays and, in the worst cases, reduced of life time. However, Down syndrome is a disorder with a wide variety of aspects that need to be considered in greater depth to understand why animals do not exactly suffer from this disorder.

What is Down syndrome?

Down syndrome is the most common form of trisomy in the human race, affecting approximately 1 in 700 births. In this sense, it is important to know that the human being has a total of 23 pairs of chromosomes and trisomy 21 is caused by an extra chromosome in this pair, which means that it no longer has 2 chromosomes, but 3. In general, Down syndrome is associated with poor cognitive development , as well as birth defects and the risk of other complications that shorten life expectancy.

However, the symptoms of this disorder can now be controlled much better than in the past, which has helped extend the lives of many people, although it is still difficult to predict, which is why it is a genetic alteration under constant study.

What are the symptoms of trisomy in animals?

The presence of an extra chromosome can have many effects. For people with Down syndrome, it usually presents as some degree of intellectual disability. However, in animals, it can vary greatly from one breed to another.

Among the most common physical symptoms are slightly spaced eyes, flattened face, short neck and small ears. They may also have white spots on the iris, small legs, loose joints, and poor muscle tone. Also, animals with trisomy can have hearing loss, ear infections, heart defects and eye diseases, such as cataracts.

primates with trisomy

In recent years, there have been reports of the occasional monkey with Down syndrome or suspected of having it. This is because they are genetically very similar to humans, so they can be affected by a disorder similar to Down syndrome. In this sense, it is important to mention that large apes, such as gorillas, have a DNA between 97 and 98% similar to the human genetic code, since they have 24 pairs of chromosomes, only one more pair than the human being.

In chimpanzees, the abnormality occurs on chromosome 22 and this can cause symptoms similar to those of people with Down syndrome, such as heart disease, underdeveloped teeth, growth retardation and some eye complications. Also, cases of trisomy have been reported in other primates, such as siamangs and macaques.

Cats with physical abnormalities similar to Down syndrome

Cats with Down syndrome have recently gained popularity on social media, but it’s important to note that the professional veterinary community has not recognized feline trisomy 21 as a real disorder. Furthermore, attribution of diseases based simply on their physical appearance or behavior is strongly discouraged, as it can be seen as disrespectful to those who actually have Down syndrome.

It is possible to see some physical characteristics in some cats that can be similar to people with trisomy 21, but it is necessary to be clear that it is not the same condition. Therefore, it is important to mention that the symptoms of trisomy occur in cats as a consequence of other health problems, such as neurological diseases , infections, traumas and other birth defects.

Similarly, some cats suffer from cerebellar hypoplasia, which is a disorder that causes characteristics and behaviors similar to those of trisomy 21, so when you see one of these animals it is easy to think that it is a cat with Down syndrome. In addition, head trauma can cause physical injury and permanent neurological damage. Also, a poor diet of the cat during pregnancy can cause the offspring to have genetic problems. Therefore, it is always good to feed the animal with a cat food according to its age and physical condition.

Can dogs have Down syndrome?

Nor is it scientifically correct to say that there are dogs with Down syndrome. Although some with similar physical characteristics may exist, they are very rare in the world. It is true that genetically dogs and humans have many similarities, but there are some important differences in their genetic code. For example, if you are wondering how many chromosomes a dog has, you should know that it has 39 pairs, so it is impossible to find a dog with Down syndrome.

However, dogs can have trisomy and in this case the most common symptoms are slow growth, large head, wide tongue, short limbs, abnormal heart rhythm, mental dullness and delayed tooth development.

Also, some developmental disorders in dogs may have some clinical similarities to Down syndrome. An example may be congenital hypothyroidism, caused by low or absent levels of thyroid hormone, which in turn is a consequence of premature birth.

Finally, it is important to remember that animals with Down syndrome are wrongly defined, since their anomalies are the consequence of some other type of disability. For more information, it is advisable to seek help from a veterinarian who can provide a better diagnosis and indicate the best possible treatment.