Muscular Distrophy.. Genetics Q

[Aimz]

X-linked recessive inheritance is when the mother passes on one faulty X chromosome (See figure below). The resulting child, male or female, has a 50% chance of inheriting the faulty gene but only the male can develop MD from it. Because the female child has two X chromosomes, one healthy X can override one inherited faulty X. In this instance however, the female child is still a carrier of the inherited faulty X and may pass it on to her children. The female child should have genetic testing to determine her status before having her own children.

Ok so this is the one that runs in our family. So there is a 50% chance that I carry the gene - that is what I thought.

So if I am tested and it is proven that I carry the gene, then there is a 50% chance of passing on that gene to my son who could then become sick with the illness later in life. Is that right?

I looked up the gender selection/IVF and you obviously have to qualify to be able to have this done (in some places they have canned it all together). Even then - isn't that majorly messing with mother nature?

On the flip side though - if I chose not to get tested and went ahead and concieved a boy, I would have knowingly put that child at risk.

[sangie]

Yes your children have a 50% chance of inheriting the gene from you but only your son would be affected by it. If I was you I would probably get tested and then worry about the implications if you need to...........cross one bridge at a time!

If you carry the gene defect then it would be really worthwhile seeing a genetic counsellor - they will be able to tell you all about your options and answer your questions much better than I can! As for messing with mother nature - well that is a decision you have to make and a genetic counsellor will help you with that. It's not uncommon in families who carry serious genetic disorders. Alternatively you may be able to screen for the gene irrespective of sex, thereby choosing not to implant affected embryos. Not saying you should do this, but these options are available.

[Aimz]

Thanks so much Sangie. I'm seeing my GP tomorrow so I might mention it to him then.

My guess is the genetic testing is going to be majorly expensive too *eek*.

[sangie]

Good luck Amy!

Not sure about the cost. Might just be a cheek swab hopefully, nice and easy!

[HotI]

Hi Amy

Sorry for more questions, but just want to check on something. Has your Dad actually had the genetic test and been told he has the same mutation (gene variation) as your uncle?

Your Nan is a carrier, but she has two X chromosomes. She passes one X chromosome on when she has a child. (And the man passes either an X or a Y, so the baby then has XX or XY). So, for each of Nan's children, they have a 50% chance of having the X with the mutation.

If your Dad hasn't had the genetic test yet, this will change your risk figure (that you are a carrier) to 25%.

Also, if the family mutation is known, a woman may be able to have PGD and select only babies that do not have the mutation. This could still be a boy, just carrying the 'healthy' X. It all depends on which gene is involved and if they can make a genetic test that will work on only one cell (which is how PGD works).

I read your other post, and i am glad you are feeling a bit better. If this post is overload, feel free to ignore it and come back when you are ready.

take care,

kate

[Aimz]

Hi Kate,

When my uncle started his testing 12 months ago, my Dad, other uncle and Nan all had bloodwork done as well. It came back that all three boys have the mutated gene, however only one has been affected by the disease. As I have previously said, that is not to say my Dad won't get the illness when he is in his senior years. So my risk of being a carrier is 50%. I probably should have clarified this earlier.

Thanks