We have located links that may give you full text access.
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Expansion of an FMR1 grey-zone allele to a full mutation in two generations.
Journal of Molecular Diagnostics : JMD 2009 July
Fragile X Syndrome is caused by the expansion of an unstable CGG-repeat tract in the 5'-UTR of the FMR1 gene, which generally results in transcriptional silencing and consequent absence of the FMR1 protein. To date, the smallest premutation allele reported to expand to a full mutation allele in a single generation is 59 CGG repeats. Here, we report a single-generation expansion to a full mutation allele (male with approximately 538 CCG repeats) from a mother who is a carrier of a premutation allele of 56 CGG repeats. Furthermore, the maternal grandfather was a carrier of a gray (or intermediate)-zone allele (45 to 54 repeats) of 52 CGG repeats. Thus, in this family, a gray-zone allele expanded to the full mutation range in two generations. Interestingly, the two AGG interruptions present in the grandfather's allele were absent in the mother's premutation allele. These observations underscore the need to consider carriers of alleles of greater than 55 CGG repeats as being at risk for transmission of a full mutation allele in a single generation, and those with even smaller alleles in the gray zone as being at risk of having grandchildren with full mutation alleles.
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app