Preimplantation diagnosis for fragile X syndrome based on the detection of the non‐expanded paternal and maternal CGG

@article{Sermon1999PreimplantationDF,
  title={Preimplantation diagnosis for fragile X syndrome based on the detection of the non‐expanded paternal and maternal CGG},
  author={Karen Sermon and Sara Seneca and Anna Vanderfaeillie and Willy Lissens and Hubert Joris and Mark Vandervorst and Andr{\'e} C. van Steirteghem and Inge Liebaers},
  journal={Prenatal Diagnosis},
  year={1999},
  volume={19}
}
Fragile X syndrome is the most common monogenic cause of mental retardation in boys. It is always characterized clinically by moderate mental retardation and often by a long face with large everted ears and macro‐orchidism. The causal mutation is an expansion of a CGG triplet repeat in a 5′ exon of the FMR‐1 gene in Xq27.3. We report here for the first time a method for preimplantation genetic diagnosis (PGD) for fragile X syndrome based on the amplification of the CGG triplet in the normal… 

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TLDR
Study of FMR–1 in sperm of four male fragile X patients showed that only the premutation was present in their sperm, although they had a full mutation in peripheral lymphocytes, which might suggest that expansion of the premutations to the full mutations in FMR-1 does not occur in meiosis but in a postzygotic stage.

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TLDR
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TLDR
The fragile X mental retardation syndrome is caused by unstable expansion of a CGG repeat and direct detection of the mutations is used to characterise large families who illustrate the wide variation in penetrance which has been observed in different sibships (a feature often called the Sherman paradox).

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TLDR
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TLDR
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TLDR
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TLDR
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