My 91-year-old father was diagnosed with Alzheimers, and my younger sister has mental retardation. What are the chances that both these conditions were caused by fragile X?
Some cases of FXTAS were initially diagnosed as Alzheimers disease (AD), since some individuals do develop memory problems and reduced mental function leading to dementia. In the case of an older adult male with symptoms of AD and a daughter with mental impairment, it is hard to state without additional information what the chances are that he has FXTAS. Was he exhibiting any tremor and/or balance problems? More than 90 percent of adults with FXTAS have one or both of those core symptoms. If he were a carrier of the premutation form of the fragile X gene, then all of his daughters would also be carriers. A small proportion of female carriers do experience cognitive difficulties, and a larger proportion experience emotional difficulties, so both the fathers and the daughters difficulties could be due to the fragile X gene. The easiest way to resolve this issue is with a fragile X DNA test, which could be performed on any of the daughters and/or the father. If he does have FXTAS, then al
