AIS mothers

[melonade]

I've had a curious question about how being an AIS carrier (mother) works. But it's not a question I've seen covered anywhere, so I need to ask known CAIS women themselves.

The way AIS is supposed to work is a mutation on the X chromosome which by a series of molecular changes renders the androgen receptors non-functional. And that the Y chromosome contains no copy of the AR gene to stop that from happening.

While in the carrier mother, the second X's copy of a good AR gene is supposed to override the AIS AR gene. But when the mother was born, one of her X chromosomes would be picked at random to be completely inactivated and become a Barr body. I can't find anything that gives a reason for why the inactivated X should be the AIS X.

So is it that 50 percent of the time, the AIS carrying mother should also have androgen insensitivity that no one cares about because she's female anyway? It should be easy to find out, because a non-androgen insensitive woman should at least have some peach fuzz somewhere on her at some point in her life.

So knowing what your mothers look like, can anyone say if they seemed reasonably androgen insensitive?

And if no AIS mothers are insensitive, then what is the biological force that makes sure the inactivated X is always the AIS X?

[miriam]

The generic genetic stuff:
http://www.aissg.org/21_OVERVIEW.HTM#GeneticsAIS

The specialist stuff:

Originally Posted by Wikipedia

Timing
All mouse cells undergo an early, imprinted inactivation of the paternally-derived X chromosome in two-cell or four-cell stage embryos.[4] The extraembryonic tissues (which give rise to the placenta and other tissues supporting the embryo) retain this early imprinted inactivation, and thus only the maternal X chromosome is active in these tissues.

In the early blastocyst, this initial, imprinted X-inactivation is reversed in the cells of the inner cell mass (which give rise to the embryo), and in these cells both X chromosomes become active again. Each of these cells then independently and randomly inactivates one copy of the X chromosome. This inactivation event is irreversible during the lifetime of the cell, so all the descendants of a cell which inactivated a particular X chromosome will also inactivate that same chromosome. This leads to mosaicism if a female is heterozygous for an X-linked gene, which can be observed in the coloration of calico cats. For an individual cell or lineage the inactivation is therefore skewed or 'non-random' this can give rise to mild symptoms in female 'carriers' of X-linked genetic disorders [5]

X-inactivation is reversed in the female germline, so that all ova contain an active X chromosome.

http://en.wikipedia.org/wiki/Lyonization

Originally Posted by melonade

So knowing what your mothers look like, can anyone say if they seemed reasonably androgen insensitive?

No. My mother and my non-AIS sister have almost no pubic hair or armpit hair. But there are also mothers and non-ais sisters who have 'normal' pubic hair. (What the heck is 'normal'?). A mother who is a carrier can also get non-ais daughters and non-ais sons and they have 'normal' pubic hair too.

Originally Posted by melonade

And if no AIS mothers are insensitive, then what is the biological force that makes sure the inactivated X is always the AIS X?

As you can read in Wikipedia there is no such force.

Groeten, Miriam

[The Female Eunuch]

Quote:

And if no AIS mothers are insensitive, then what is the biological force that makes sure the inactivated X is always the AIS X?

Miriam

As you can read in Wikipedia there is no such force.

But the bit you posted from Wikipedia is about mice. In a human, the same X is inactivated in every cell.

cheers,
Caroline

[fraulein_Maria]

[quote=The Female Eunuch;16913]
But the bit you posted from Wikipedia is about mice. In a human, the same X is inactivated in every cell.

cheers,
Caroline

>>> are you quite sure? mice are not used for comparison because they closely resemble humans (pigs are MUCH closer but because its cheaper to do research with them as models.

[melonade]

Originally Posted by miriam

The generic genetic stuff:
http://www.aissg.org/21_OVERVIEW.HTM#GeneticsAIS

The specialist stuff:






No. My mother and my non-AIS sister have almost no pubic hair or armpit hair. But there are also mothers and non-ais sisters who have 'normal' pubic hair. (What the heck is 'normal'?). A mother who is a carrier can also get non-ais daughters and non-ais sons and they have 'normal' pubic hair too.


As you can read in Wikipedia there is no such force.

Groeten, Miriam

Thank you Miriam, that was very informatiive. What you are saying about how some mothers are less hirsuit than normal while others are normal does agree with my thought that maybe 50 percent of the carrier mothers would express their AIS X. That doesn't necessarily conflict with having uneffected sisters. Only 50 percent would get an AIS X from their carrier mother, only 50 percent of the 50 percent carriers would express it. If nothing prevents it, then it must happen to someone.

[fraulein_Maria]

My mother and my non-AIS sister have almost no pubic hair or armpit hair.

>>> so although they are known carriers, but not AIS'ers (either C or P) this sign of local tissue androgen insensitivity is no indicator of carrier status? <<

But there are also mothers and non-ais sisters who have 'normal' pubic hair.

>>> that may be so, but there are other tissues that might be affected besides hair follicles. it could be said that i am androgen insensitive in the beard region; asiatics of BOTH genders often are. But it would be a mistake to then assume that other tissues were insensitive also

Perhaps the carriers with pubic and accillary hair might have.... a low red cell count... because there bone marrow which in everyone else is androgen sensitive... is not.

XX CAH's have a high red cell count in comparison to there "normal" sisters, as do XX CAH carriers, because the production rate of them is DIRECTLY related to blood levels of testosterone, and sensitivity to it.

In regards to AIS'ers this is obviously conjecture on my part, but i hope i have given you interesting thoughts. <<<

As you can read in Wikipedia there is no such force.

>>> i would venture to say that if any such force existed, it would simply be the tendency of self-replicating and self-repairing systems to function. the primordial immune system ensuring that primordial replication accurately takes place. <<<

[The Female Eunuch]

Maria wrote:

>>> are you quite sure? mice are not used for comparison because they closely resemble humans (pigs are MUCH closer but because its cheaper to do research with them as models.

how does the fact that mice are genetically less like us than pigs are conflict with the idea that the switching off of X chromosomes in humans happens differently from how it does in mice?

surely, if anything, our genetic difference from mice makes it more likely that we would deal with extra X-chromosomes differently from how mice do?

[fraulein_Maria]

[quote=The Female Eunuch;16928]Maria wrote:

how does the fact that mice are genetically less like us than pigs are conflict with the idea that the switching off of X chromosomes in humans happens differently from how it does in mice?

surely, if anything, our genetic difference from mice makes it more likely that we would deal with extra X-chromosomes differently from how mice do?

>>> my apologies. i mis-understood. i thought you were saying the opposite.

[The Female Eunuch]

Maria wrote:

>>> my apologies. i mis-understood. i thought you were saying the opposite.

Thanks. So if we agree that in XX humans every cell in the body has the same X chromosome switched off, then I'm pretty certain we still haven't answered the question of why an XX woman with one AIS X-chromosome cannot have androgen insensitivity.

I'd still be interested to know.

Oh, and Thank you Miriam for posting that AISSQ URL. It didn't answer this question, but led me to some other interesting stuff (including an example of a transsexual group trying to hijack intersex concerns).

cheers,
Caroline