1. Mosaicism in Fragile X syndrome: A family case series.
- Author
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Saldarriaga W, González-Teshima LY, Forero-Forero JV, Tang HT, and Tassone F
- Subjects
- Female, Fragile X Mental Retardation Protein genetics, Fragile X Mental Retardation Protein metabolism, Humans, Male, Mosaicism, Mutation, Phenotype, Fragile X Syndrome complications, Fragile X Syndrome diagnosis, Fragile X Syndrome genetics, Intellectual Disability complications, Intellectual Disability genetics
- Abstract
Fragile X syndrome (FXS) has a classic phenotype, however its expression can be variable among full mutation males. This is secondary to variable methylation mosaicisms and the number of CGG triplet repeats in the non-coding region of the Fragile X Mental Retardation 1 ( FMR1 ) gene, producing a variable expression of the Fragile X Mental Retardation Protein (FMRP). Here we report a family with several individuals affected by FXS: a boy with a hypermethylated FMR1 mutation and a classic phenotype; a man with an FMR1 gene mosaicism in the range of premutation (PM) and full mutation (FM), who has a mild phenotype due to which FXS was initially disregarded; and the cases of four women with a FM and mosaicism. This report highlights the importance of DNA molecular testing for the diagnosis of FXS in patients with developmental delay, intellectual disability and/or autism due to the variable phenotype that occurs in individuals with FMR1 mosaicisms.
- Published
- 2022
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