Fragile X syndrome due to a missense mutation
Paediatrics and Child Health
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.
European Journal of Human Genetics
Myrick, L. K.,
Lindor, N. M.,
Warren, S. T.
(2014). Fragile X syndrome due to a missense mutation. European Journal of Human Genetics, 22(10), 1185-1189.
Available at: https://ecommons.aku.edu/pakistan_fhs_mc_women_childhealth_paediatr/1245