Dog Health & Care

Down Syndrome in Dogs

Down syndrome in dogs was originally thought to be the only chromosomal defect in all mammals. Usually the pregnant mother aborts or rejects the fetus because of the abnormality, a number one reason down syndrome in dogs or animals is not a problem we hear much about.

However, because of the findings of the Dog Genome Project we have found that dog genome projectthe domesticated dog is a very close evolutionary relation to the human. By understanding the genetics of the dog, disease mappings have resulted in over 1,800 DNA markers in dogs and 320 dog genes.

It has been found that there are underlying diseases shared between the dog and people — a skin disease known as ichthyosis, muscular dystrophy, von Willebrand’s disease, cancer, diabetes, and epilepsy. Basically, it has been found that any disease humans get, the dog can get also.

“We dog researchers are not working in the dark,” says Keith E. Murphy of Texas A&M University, whose team recently sequenced the keratin gene, KRT2p, and mapped it to chromosome 27 of the dog. “The great progress in human genetics means that if you have a disease that presents the same way in humans and dogs, you can almost go straight to the gene in the dog.”

Studies done by the Human Genome Project are being done by researchers of the human chromosome 21, along with studies at the Dog Genome Project. Over 95% of all cases list the cell as having two 21 chromosomes instead of just one, consisting of 200 to 250 genes. Down syndrome is considered a chromosomal abnormality because of an “extra copy of genetic material” placing itself on the 21st chromosome, resulting in a trisomy of the 21st chromosome.

The projects have sequenced the base pair that forms chromosome 21, the second human chromosome ever to be fully sequenced. Other diseases associated with genes of this chromosome are Alzheimer’s Disease, Leukocyte adhesion deficiency, Majewski osteodysplastic primordial dwarfism type II, homocystinuria, Roman-Ward syndrome, and Erondu-Cymet syndrome. According to the Dog Genome Project, ” On the evolutionary tree, the dog is somewhere between humans and mice. Sequences that are conserved in all three species are likely to be in the human genome for a reason.”

down syndrome in dogsThe studies have also found that the reasons dogs are loyal to humans is because it is the same type of relationship that corresponds to their natural social patterns. Each individual has a rank, with the dog always aware of its position within a group. In fact, the dog genome is the same as the human genome but divided into 70 pieces with a greater number of chromosomes.

The mapping of the 21 chromosome in dogs has demonstrated not downs syndrome, but a genetic diversity unlike any other mammalian on earth. The huge diversity of the canine has been influenced by the human’s direct breeding — channeling it into a storage of inherited diseases, behaviors and morphologies. This has made possible the dog’s genome sequencing and SNP mapping to allow us to see the similar genetics of disease and normal biology between  dogs and mankind.


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  1. March 30, 2013 at 1:02 am — Reply

    For babies, down syndrome can be diagnosed just by looking at the baby at birth. The facial features and characteristics can tell you that. But tests need to be done; karyotype – a blood or tissue sample stained to show chromosomes grouped by size, number, and shape – will be performed to verify the diagnosis.

    Dogs are no different. The face has the same odd appearances to look for, but testing is needed to further the diagnose. Even though the chromosome error would be the same as in a human child, quite possibly the studies may call it under another name.

    Here is some info for you:

    Symptoms and treatments of down syndromes in dogs < >

    Image of a tiger with a down-syndrome look: < >

    Image of a down syndrome look in a kitten:
    < >

    Vetblog < >

    Hope this helps, as the research is new. Therefore, not a lot of info is out yet.

  2. Where can i find photos of a boxer dog who has this?

    • March 30, 2013 at 1:04 am — Reply

      Also, Lisa. The boxer dog does have a look of its own, similar to a down syndrome dog. However, unless the blood was tested, I would not trust a photo due to their wide spread eyes and mouth position. Otherwise, every boxer would be diagnosed as one! haha

  3. nia major
    April 19, 2012 at 12:39 pm — Reply

    but how can we tell if our puppy has this ?

    • April 19, 2012 at 3:40 pm — Reply

      Have it checked at your local vet.

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