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If you have fragile x and have kids?

Posted by on Sep. 28, 2010 at 6:13 PM
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 Ok i have a question for you ladies. Im a carrier of the fragile x syndrome and so does my son we found out a few months ago that we both have it. Now does that mean all my kids i would have have it? I would like more then one child but not sure if all the kids i would have also have the fragile x syndrome.

by on Sep. 28, 2010 at 6:13 PM
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by Group Owner on Sep. 28, 2010 at 7:22 PM

There is a risk for each child that you would have to either be a carrier of or have the full mutation. Is your son a carrier of does he have the full mutation of FX? I have 3 boys the oldest two have FX and my youngest does not. So there is a chance that the next child could be completely unaffected.

by Member on Sep. 28, 2010 at 9:46 PM

 I have 3 out of my 6 that have FX. I was told it is a 50/50 chance. Because one of your x chromosomes is good and one is bad. So it depends on which one they get.

by Member on Sep. 29, 2010 at 8:32 AM

For a female carrier (and a carrier could be one with a pre or full mutation) with each pregnancy there is a 50/50 chance of passing the condition on, but that doesn't mean every child will be affected, it will depend are they a pre-mutation or a full-mutation, are they a boy or a girl, a lot comes into play.  For basic inheritence I think the Your Genes Your Health Website explains it well in laymans terms, - fragile X page.

For my family, my mother was a carrier, my older sister had a full mutation but did not pass it on to her two children, I am a pre-mutation and passed a full mutation on to 3 of my 4 children, my younger sister didn't get my mother's mutated FMR1 gene, she got the other X chromosome which is in the normal range so she is not a carrier of the mutated FX gene.

One must keep in mind fragile X is a spectrum disorder and that spectrum can be huge in females, my daughters with FX do NOT have 504s or IEPs, they are in regular ed, honor role or ALL A student.  One must keep in mind they could have just as easily fallen into the other end of the spectrum, 1/3 of girls have no symptoms, 1/3 have learning disabilities, 1/3 have challenges as severe as some of their male counterparts.

Hugs, Sally


by Member on Sep. 29, 2010 at 4:47 PM

 You should get tested to see how many CGG repeats you have. I have 89 repeats on one x (the affected x), and 26 on the other. Since I have such a high number on the affected x, it is a 75% chance our next child would be affected (whether boy or girl). You can request your blood to be tested from either your doctor or your childs doctor.  

by Member on Sep. 30, 2010 at 8:28 AM


Not sure where you are getting the 75% from, but there is NOstudy that can determine if the child will or will not be affected.

The most reliable study on expansion was done by Nolin in 2003, and the precentages it can provide is the risk of the premutation EXPANDING to a full mutation, not sure if this chart will transfer over correctly but we'll see:

Table 5. Risks for Expansion from a Maternal Premutation to a Full Mutation When Transmitted to Offspring

Number of Maternal Premutation CGG Repeats Total Maternal Transmissions Expansions to Full Mutations (%) 1
55-59 27 1 (3.7%)
60-69 113 6 (5.3%)
70-79 90 28 (31.1%)
80-89 140 81 (57.8%)
90-99 111 89 (80.1%)
100-109 70 70 (100%)
110-119 54 53 (98.1%)
120-129 36 35 (97.2%)
130-139 18 17 (94.4%)
140-200 19 19 (100%)

Adapted from Nolin et al [2003]

According to Nolin's study with 89 repeats you have 57.8% of having a child with the expanded CGG repeat (full mutation) and one must keep in mind that especially with a female child an expanded CGG repeat does not mean they will be affected.

by on Sep. 30, 2010 at 11:29 AM

 its always a gamble.  I feel if you really want a second child and you are ready to accept the responsibility of a child with fxs then go for it.  There are also other ways to try to have a child without fxs but its still a gamble.  the nfxf website include information on your reproduction options :)

by Member on Sep. 30, 2010 at 1:33 PM

 Sally, I wish I could scan the chart the doctor gave to me, it looks TOTALLY different from yours. :/

I'll see if I can do that today. I'm sorry, but I'm going to go by what my doctor told me and the chart she gave to me. No offense though, I just don't always believe what is on the internet.

Oh and I guess I have to be more careful with my words. I shouldn't have said 75% chance they will be affected, but 75% they will have the Fragile X gene. Which to me, is the same thing.

by Member on Oct. 1, 2010 at 7:21 AM

I'd like to see the source, one must keep in mind, sometimes doctors also rely on information from the internet. I spent five years working on a project with FRAXA, NFXF, CDC, Genetic Alliance, NIH and Univ of Maryland on access to credible genetic information, one of the final outcomes of the project was a tool to help individuals evaluate information on the web, it's available at:: 

My source is, they have peer reviewed, expert-authored articles on diseases written for physicians, healthcare providers and researchers. Supported by NCBI (National Center for Biotechnology Information,

Do you visit a Fragile X Clinic? Curious.


by Member on Oct. 1, 2010 at 12:32 PM

All the charts in the world won't matter if your child is the one.  I have three children, the oldest is a carrier and has such anxiety that he may as well be a full mutation.  My middle son has full mutation along with Autism.  It is heart breaking and I wish I had known before we chose to have a third.  The great news is, she is typical.  I am happy we have her and feel so blessed to have been given this gift, but, I see the burden that having a sibling as badly affected as my son is taking on her and my oldest.  The reality is that it is what it is...  all our children are wonderful and it is just so important to know that if you choose to have more, there is always that chance.

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