What are the chances of someone with Fragile X Syndrome passing it on to someone else?

Males who are carriers will pass on the gene to all of their daughters, they will be FX carriers. Females who have the premutation (50-200 CGG repeats) or full-mutation (over 200 CGG repeats) have a 50/50 chance of passing it on with each pregnancy. Now just because they pass it on doesn't mean the child will be affected (especially when it comes to girls, since girls have 2 X chromosomes, the other X may produce enough protein.)