FXTAS in an unmethylated mosaic male with fragile X syndrome from Chile

Lorena Santa María, A. Pugin, M. A. Alliende, S. Aliaga, B. Curotto, T. Aravena, H. T. Tang, G. Mendoza-Morales, Randi J Hagerman, Flora Tassone

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Carriers of an FMR1 premutation allele (55-200 CGG repeats) often develop the neurodegenerative disorders, fragile X-associated tremor/ataxia syndrome (FXTAS). Neurological signs of FXTAS, parkinsonism and rapid onset of cognitive decline have not been reported in individuals with an unmethylated full mutation (FM). Here, we report a Chilean family affected with FXS, inherited from a parent carrier of an FMR1 unmethylated full mosaic allele, who presented with a fast progressing FXTAS. This case suggests that the definition of FXTAS may need to be broadened to not only include those with a premutation but also those with an expanded allele in FM range with a lack of methylation leading to elevated FMR1-mRNA expression levels and subsequent RNA toxicity.

Original languageEnglish (US)
Pages (from-to)378-382
Number of pages5
JournalClinical Genetics
Issue number4
StatePublished - 2014


  • Fragile X
  • Parkinsonism
  • Unmethylated full mutation

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics


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