Fragile X syndrome due to a missense mutation

Leila K. Myrick, Mika Nakamoto-Kinoshita, Noralane M. Lindor, Salman Kirmani, Xiaodong Cheng, Stephen T. Warren

Research output: Contribution to journalArticlepeer-review

65 Citations (Scopus)


Fragile X syndrome is a common inherited form of intellectual disability and autism spectrum disorder. Most patients exhibit a massive CGG-repeat expansion mutation in the FMR1 gene that silences the locus. In over two decades since the discovery of FMR1, only a single missense mutation (p.(Ile304Asn)) has been reported as causing fragile X syndrome. Here we describe a 16-year-old male presenting with fragile X syndrome but without the repeat expansion mutation. Rather, we find a missense mutation, c.797G>A, that replaces glycine 266 with glutamic acid (p.(Gly266Glu)). The Gly266Glu FMR protein abolished many functional properties of the protein. This patient highlights the diagnostic utility of FMR1 sequencing.

Original languageEnglish
Pages (from-to)1185-1189
Number of pages5
JournalEuropean Journal of Human Genetics
Issue number10
Publication statusPublished - 11 Oct 2014
Externally publishedYes


  • FMR1 sequencing
  • fragile X syndrome
  • missense
  • mutation


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