Weird question on abnormal human anatomy (hoping it not being the case)

[EnumaElish]

Over the long weekend I was touring a museum whence I glanced upon a thirtysomething woman and had to look again. There was a tiny arm coming out of her chest. I thought she must be carrying her tiny baby in a receiver (?) shawl wrapped around her, but did not inquire personally. I might have seen part of her baby, or imagined it for fear of imagining the alternative...

My question is, could it have been something else?

 

[BoomBoom]

It is possible during development of a fetus for a faulty signal to be sent or received in which a group of cells may develope into something they are not supposed to be. Expression of the genes within cells determines what type of cell it becomes.

 

[chroot]

I find it pretty hard to believe.

First, mutations in the genes that determine body structure (like the Hox genes) usually cause incorrect branching. The organism will have more or fewer fingers, extra legs, that sort of thing -- but they will all be errors at the branching points, where the legs split and diverge. I'm not a biologist, but the chances of a single-point Hox mutation causing an arm to grow out a really abnormal place -- and not a branching point, like one's chest -- seem pretty small to me. A large number of mutations would result in death.

Also, I find it hard to believe that anyone growing up in an affluent western society would not have had surgery very early in life to remove the abnormality.

I wasn't there, of course, but I really think you must have just mistaken what you saw.

- Warren

 

[Danger]

You didn't happen to notice any strange lights or unusual looking eggs in the vicinity, did you?

I mostly agree with Chroot. It's fairly common for lesser-developed species (especially reptiles and amphibians) to grow things in weird places, but very rare in people. I've heard of it happening, though. Most assuredly, though, something like that would have been surgically corrected. She was probably just feeding the kid or something, and part of it got away.

 

[turbo]

Darn it! Kuarto still gets no respect.

 

[BoomBoom]

I agree that an extra appendage is not what you saw. I was just commenting that such a thing is possible. :)

I heard a story a few years ago about a huge tumor that doctors removed from a women's abdomen and in the biopsy they actually found hair and teeth. These cancer cells were actually expressing themselves as completely different cells. Of course I don't have a reference to this, so can't comment on the legitimacy of the story, but it was on a Discovery or Nova type program.

I agree that a single point mutation in a Hox gene (there are 10 of them) would do nothing. There are more key factors to appendage growth though, like Sonic hedgehog for instance which seems to play a key role in the development of limbs.
http://en.wikipedia.org/wiki/Sonic_hedgehog

 

[hypatia]

I recall from my studies years ago, that most cases of{non-Hox} multiple limbs result from conjoined twins forming in development. One child does not survive and becomes essentially absorbed into the other. You may see a foot or arm on any part of the body.

 

[Moonbear]

I recall from my studies years ago, that most cases of{non-Hox} multiple limbs result from conjoined twins forming in development. One child does not survive and becomes essentially absorbed into the other. You may see a foot or arm on any part of the body.

This is pretty much the only reason this would make sense (a non-surviving conjoined twin event), especially if it was protruding from someplace other than the shoulder. However, as Chroot pointed out, unless this is someone who has only recently moved from a very poor country, such an obvious deformity would have been surgically removed during childhood. Most likely, you really did see a baby swaddled up in one of those slings people use for carrying them (or perhaps the scarf was hiding the fact she was breast feeding an infant, which is why you only saw an arm sticking out).

 

[mgb_phys]

I heard a story a few years ago about a huge tumor that doctors removed from a women's abdomen and in the biopsy they actually found hair and teeth. These cancer cells were actually expressing themselves as completely different cells.

This is fairly common in tumours.