FXTAS, welcome! I have been reading what you posted, along with other things. Yes, some symptoms are alike but Fragile X Syndrome is, according to the National Institute of Health, a form of inherited mental retardation. I have had fibro for 21 years and haven't had these problems. Here is the link to that.
You probably are not misdiagnosed. My son is ADHD and I'm diabetic but that doesn't mean I have Fragile X Syndrome. Many illness share the same symptoms. Have you checked out the Fibro 101 thread...the second thread on the forum? There is a lot of info on fibromyalgia, including a list of symptoms we have along with a link to "What Else Could It Be". You will see that fibro mimics several other illnesses, including MS and lupus. Naturally, if you are getting Parkinson-type tremors, etc., you need to discuss it with your doctor.
Continue to read past posts and this may just settle your mind down. If you are truly that concerned, then ask for the testing for Fragile X Syndrome. I hope you get the answers you need.
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Fibromyalgia, Crohn's Disease, Ostomy, Diabetes, Autoimmune Inner Ear Disease, Osteoporosis
God does not give us a spirit of fear, but of power and of love and of a sound mind. 2 Timothy 1:7