News tagged with fragile x syndrome

Related topics: brain · autism

Alzheimer's missing link found

Yale School of Medicine researchers have discovered a protein that is the missing link in the complicated chain of events that lead to Alzheimer's disease, they report in the Sept. 4 issue of the journal Neuron. Researchers ...

Sep 04, 2013
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Researchers target an aspect of Down syndrome

University of Michigan researchers have determined how a gene that is known to be defective in Down syndrome is regulated and how its dysregulation may lead to neurological defects, providing insights into potential therapeutic ...

Jun 05, 2013
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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.

This text uses material from Wikipedia, licensed under CC BY-SA

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