Apart from monkeys or the ape family, in what other species has Down's syndrome been detected?

Mice can have downs as well and science is using them to study the issue. It is caused by the presence of all or part of an extra 21st chromosome.

Not really the same, but any animal that has a body and a brain can have genetic defects that can impair body and brain function, such as this cat;
http://www.youtube.com/watch?v=6g6jiyJCRpU
while the owner labeled it as a downs syndrome cat, it’s technically incorrect.

It is not found naturally in mice; the mice with Downs are genetically engineered. It’s only been found naturally in primates.

Oh I wasn’t aware that the question said what species have downs naturally?

Years ago I had a cat that had kittens and one kitten had the facial traits of downs syndrome and was very slow to mature. I have no doubt that kitten had mental retardation. It was adopted and I never followed up on it’s situation but, it definitely had what I believe to be a type of Downs syndrome.

@Coloma

“Down’s syndrome” is a very specific disorder. In humans and other primates, it’s caused by a duplication of all or part of chromosome 21, so that the individual has three copies of this chromosome. In cats, which have a very different chromosomal structure, a real equivalent of Down’s syndrome isn’t naturaly possible. However, some other trisomies could be found- Klinefelter’s syndrome, in which the animal has an extra copy of an X chromosome and thus the karyotype XXY, is responsible for the very rare occurrences of male calico cats.

@crisw

All I know is that kitten had funny almond shaped eye’s, a strange facial arrangement and was very comprimised in it’s abilities…who knows.

Lots of ‘rarities’ can occur that may not be probable nor well documented.

@Coloma

Interestingly, mosaic trisomy is responsile for some cases of leukemia in cats. Other autosomal trisomies have been observed in cats as well. So it’s certainly possible that your cat had a genetic defect- it just wasn’t Down’s syndome. There are quite a few different trisomies in humans, and almost all of them have very characteristic facial defects. I assume the same would be true in cats as well.

@crisw

Makes sense, I never researched the condition, just observed it seemed like a mental and physical defect like DS. You have provided some interesting info. Thanks. :-)

@JustmeAman Sorry if I caused any ambiguity in my question but when I said “detected” I meant naturally occurring and I exclude genetically engineered in my original meaning.

crisw : great answers. If you have more to add on the topic please feel free to share. My next question is :

“Does anyone have any other hypothesis/guesses (apart from mother’s age and extra copy of Chromosome 21) on the cause of Down’s Syndrome?”

@shalom

If you are talking about the genetic cause, there really don’t need to be any other hypotheses. We know that a trisomy, partial trisomy, or mosaic trisomy of chromosome 21 causes Down syndrome.

If you are talking about what causes the trisomy in the first place- advanced maternal age is one known culprit. Advanced paternal age also is a cause.

Chromosome 21 is one of our smallest autosomal chromosomes. When sperm and eggs form and cells divide, the chromosomes can “stick together” in the sperm or egg cell. This is called a “nondisjunction event” and is reponsible for about 95% of cases of Down syndrome. Sometimes this nondisjunction event occurs after the zygote has formed, leading to an embryo with some normal cells and some trisomic cells. This is mosaic Down syndrome.

The additional 5% of cases are caused by what is called a Robertsonian translocation where part of chromosome 21 in one parent is attached to another chromosome.

The symptoms of Down syndrome are caused by the overproduction of the proteins coded for on chromosome 21.