In contrast to FXS full mutation, which is diagnosed early in childhood, symptoms of FXTAS manifest in individuals over the age of 50.[1] Like FXS, FXTAS is most common and most severe in males due to the mutation's X-linked inheritance pattern.[2] FXTAS has an incidence of 30-40% (male) and 8-15% (female) among FXS premutation carriers over the age of 50.[2][3]
FMR1mRNA is found to be elevated in patients with FXTAS[7] in contrast to FXS, where the FMR1 gene is transcriptionally silenced via DNA methylation.[8] In both diseases the FMR1 gene product, Fragile X mental retardation protein (FMRP) is diminished, but in FXTAS this is believed to be mediated by RNA toxicity, while in FXS, FMRP is absent due to transcriptional silencing.[7]
There is no cure for FXTAS, but several of the symptoms can be managed with medication.[7]
^ abcdSaul, Robert A.; Tarleton, Jack C. (1993). "FMR1-Related Disorders". In Pagon, Roberta A.; Adam, Margaret P.; Ardinger, Holly H.; Wallace, Stephanie E.; Amemiya, Anne; Bean, Lora J.H.; Bird, Thomas D.; Ledbetter, Nikki; Mefford, Heather C. (eds.). GeneReviews. Seattle (WA): University of Washington, Seattle. PMID20301558.