Down Syndrome in Dogs

Down Syndrome in Dogs

Author WDF Staff


Dogs and humans share many similarities, and we even have some similar diseases that can affect our dogs and us. However, there are differences on a cellular level that will have a completely different impact on humans and dogs’ genetic disorders. One of these genetic disorders dog owners often talk about is Down syndrome. If you want to know more about this disorder and whether it can happen to our dogs, stick with us, and you can find out.

What is Down syndrome?

To understand Down syndrome in dogs, we need to understand what it is and how it affects us. According to Healthline, it can be defined as

Down syndrome (sometimes called Down’s syndrome) is a condition in which a child is born with an extra copy of their 21st chromosome — hence its other name, trisomy 21. This causes physical and mental developmental delays and disabilities.”

This full or partial chromosome copy caused by abnormal cellular division will have a significant effect on those that are affected by it. Luckily, our society is developed. Different government programs and medical advances allow people with Down syndrome to live a full and happy life.

Before we talk about Down syndrome in dogs, we need to know how it affects the development of human babies. This syndrome is easy to diagnose, and some of the signs of Down syndrome in humans are;

  • A flattened face, particularly the bridge of the nose
  • A shorter neck
  • Small ears
  • Almond-shaped eyes that slant up
  • A tongue that tends to stick out of the mouth
  • Tiny white spots on the colored part of the eyes (iris)
  • Poor muscle tone
  • Shorter height

Unfortunately, this is not where its health issues end. People with Down syndrome are often affected by;

  • Hearing loss
  • Ear infections
  • Eye problems
  • Obstructive sleep apnea
  • Heart defects present at birth

Cellular difference between dogs and humans

Dogs and humans are different species, and as different species, we have different cells. Our genetic material is stored in each cell’s nucleus in our body, and the same is true for dogs. However, in our nucleus, there are 23 pairs of chromosomes. Dogs have 39 chromosome pairs.

About 1 in 700 babies in the US are born with Down syndrome, and the same statistic cannot be said about puppies. The effect of the irregular duplication of the 21st chromosome would probably have a completely different effect on dogs than it does on humans.

Down syndrome in dogs - does it exist?

By its definition, Down syndrome is “an extra full or partial copy of the 21st chromosome.” In dogs, there are no cases like that. Even if something like that would happen, there is no way of knowing how it would affect them. The closest thing scientists noticed to Down syndrome in the animal kingdom is in mice. Scientists did experiments and genetically mutated mice to have an extra chromosome. They achieved the same physical effects in mice as can be noticed in humans with Down syndrome.

There simply weren’t any recorded cases of genetic mutations or effects that would affect dogs as they affect humans. There are three possible reasons for that, and they are;

  • It simply doesn’t exist.
  • Such abnormalities cause early death in puppies.
  • There is no genetic testing that could identify dogs with the canine version of Down syndrome.

All of these theories are yet to be proven or disproven. For now, all of us are open to using whichever definition we believe to be most likely.

Are there other conditions that look like Down syndrome in dogs?

Although Down syndrome in dogs might not exist, other health conditions could easily confuse owners into thinking their dogs have Down syndrome. Some of these conditions are;

  • Pituitary dwarfism
  • Congenital hydrocephalus
  • Portosystemic shunt
  • Growth hormone deficiency
  • Congenital hypothyroidism

The best example is probably congenital hypothyroidism. This health condition is often confused with Down syndrome in dogs. Some of the symptoms of this condition are;

  • Broad head
  • Large, protruding tongue
  • Poor muscle tone
  • Slow growth resulting in poor development
  • Delayed opening of the eyes and ears
  • Delayed tooth eruption
  • Mental dullness

If you notice anything like these symptoms in your dog, you should call your vet and schedule an appointment. Your dog might need treatment, and your vet can tell you all about it.

World Dog Finder team

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