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Characterization of the full fragile X syndrome mutation in fetal gametes

Nature Genetics volume 15, pages 165–169 (1997)Cite this article

Abstract

Fragile X syndrome results from the expansion of the CGG repeat in the FMR1 gene. Expansion has been suggested to be a postzygotic event with the germline protected. From an analysis of intact ovaries of full mutation fetuses, we now show that only full expansion alleles can be detected in oocytes (but in the unmethylated state). Similarly, the testes of a 13-week full mutation fetus show no evidence of premutations while a 17-week full mutation fetus exhibits some germ cells with attributes of premutations. These data discount the hypothesis that the germline is protected from full expansion and suggest full mutation contraction in the immature testis. Thus, full expansion may already exist in the maternal oocyte, or postzygotic expansion, if it occurs, arises quite early in development prior to germline segregation.

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Author information

Author notes

  1. Jack C. Tarleton

    Present address: Mission Genetics Center, Asheville, NC, 28803, USA

Authors and Affiliations

  1. Howard Hughes Medical Institute and Departments of Biochemistry and Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA

    Henry E. Malter, Jane C. Iber & Stephen T. Warren

  2. Department of Clinical Genetics, Erasmus University, Rotterdam, The Netherlands

    R. Willemsen, Esther de Graaff & Ben A. Oostra

  3. Greenwood Genetics Center, Greenwood, SC, USA

    Jack C. Tarleton

  4. Oulo University, Finland

    J. Leisti

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  1. Henry E. Malter
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  2. Jane C. Iber
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  4. Esther de Graaff
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Correspondence to Stephen T. Warren.

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Malter, H., Iber, J., Willemsen, R. et al. Characterization of the full fragile X syndrome mutation in fetal gametes. Nat Genet 15, 165–169 (1997). https://doi.org/10.1038/ng0297-165

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  • DOI: https://doi.org/10.1038/ng0297-165

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