Related topics: brain · autism

Study offers new insights into fragile X syndrome

A new study shows that many abnormalities in fragile X syndrome cells are related to glitches with one of the body's major quality control systems. Published in Nature Cell Biology, the research provides fresh insight into ...

DNA repeats—the genome's dark matter

Expansions of DNA repeats are very hard to analyze. A method developed by researchers at the Max Planck Institute for Molecular Genetics in Berlin allows for a detailed look at these previously inaccessible regions of the ...

Neural stem cells serve as RNA highways too

Duke University scientists have caught the first glimpse of molecules shuttling along a sort of highway running the length of neural stem cells, which are crucial to the development of new neurons.

Secret funding fosters hope for new drugs for autism

Funding from an anonymous wealthy family has been the secret to progress, at long last, in developing drugs that show promise for helping millions of people worldwide with Fragile X syndrome, the most common genetic cause ...

Same disease, different stem cell models

In the last three years, a new technique for reprogramming adult cells has given scientists an easier and less controversial way to harness the power of embryonic-like stem cells to study human disease from its earliest beginnings ...

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Fragile X syndrome

Fragile X syndrome, or Martin-Bell syndrome, is a genetic syndrome which results in a spectrum of characteristic physical, intellectual, emotional and behavioural features which range from severe to mild in manifestation.

The syndrome is associated with the expansion of a single trinucleotide gene sequence (CGG) on the X chromosome, and results in a failure to express the FMR1 protein which is required for normal neural development. There are four generally accepted forms of Fragile X syndrome which relate to the length of the repeated CGG sequence; Normal (29-31 CGG repeats), Premutation (55-200 CGG repeats), Full Mutation (more than 200 CGG repeats), and Intermediate or Gray Zone Alleles (40 - 60 repeats).

Martin and Bell in 1943, described a pedigree of X-linked mental disability, without considering the macroorchidism (larger testicles). In 1969 Chris and Weesam first sighted an unusual "marker X chromosome" in association with mental disability. In 1970 Frederick Hecht coined the term "fragile site".

Renpenning's syndrome is not synonymous with the syndrome. In Renpenning's syndrome, there is no fragile site on the X chromosome. Renpenning's cases have short stature, moderate microcephaly, and neurological (brain) disorders.

Escalante's syndrome is synonymous with the fragile X syndrome. This term has been used in Brazil and other South American countries.

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