Fragile x syndrome, is it preventable, how?

No: Not known to be preventable. Diagnosis is made by genetic testing. No medication to specifically treat fragile x. Treatment is aimed at the effects from autism, tremors, etc.

Not preventable: while there is no way to prevent fragile X disorder, treatment with folic acid, a vitamin can be helpful with the behaviours if necessary. Behavioral therapy, applied behavioral analysis, A variety of medications are available for symptoms. You should consult a specialist working with children with Fragile X.