Prenatal Diagnosis of Fragile X: Can a Full Mutation Allele in the FMR1 Gene Contract to a Normal Size?
Here we describe a case of a prenatal diagnosis of a male fetus that inherited the unstable allele from his full mutation mosaic mother (29, 160, >200 CGG repeats) reduced to a normal size range (19 CGG repeats). Haplotype analysis showed that the fetus 19 CGG repeats allele derived from the...
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Frontiers Media S.A.
2017-11-01
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| Series: | Frontiers in Genetics |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fgene.2017.00158/full |
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| author | Esther Manor Esther Manor Azhar Jabareen Azhar Jabareen Nurit Magal Nurit Magal Arei Kofman Arei Kofman Randi J. Hagerman Flora Tassone Flora Tassone |
| author_facet | Esther Manor Esther Manor Azhar Jabareen Azhar Jabareen Nurit Magal Nurit Magal Arei Kofman Arei Kofman Randi J. Hagerman Flora Tassone Flora Tassone |
| author_sort | Esther Manor |
| collection | DOAJ |
| description | Here we describe a case of a prenatal diagnosis of a male fetus that inherited the unstable allele from his full mutation mosaic mother (29, 160, >200 CGG repeats) reduced to a normal size range (19 CGG repeats). Haplotype analysis showed that the fetus 19 CGG repeats allele derived from the maternal unstable allele which was inherited from his maternal grandmother. No size mosaicism was detected by testing the DNA from in vitro cultured samples, including seventh passage culture as well as from two amniocentesis samples. Sequence analysis confirmed that the allele was 19 CGG repeats long. Methylation assay showed no methylation. Although none of the techniques used in this study can provide with absolute certainty the diagnosis, the results strongly indicate the presence in the fetus of an allele with a CGG repeat number in the normal range. Because this is a prenatal diagnosis case, the crucial question is whether the 19 CGG allele derived from the maternal unstable expanded allele, which contracted to the normal range, became a normal stable allele or a normal unstable allele which could expand in the next generation. It is also possible that allele size mosaicism of the FMR1 gene that went undetected exists. Because this is a prenatal diagnosis case, we cannot with certainty exclude the presence of an undetected expanded allele of the FMR1 gene, in addition to the 19 CGG allele derived from an unstable expanded allele, which contracted to the normal range. |
| first_indexed | 2024-04-13T04:48:09Z |
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| id | doaj.art-9e0704561f234fa09f45334b88e90a0f |
| institution | Directory Open Access Journal |
| issn | 1664-8021 |
| language | English |
| last_indexed | 2024-04-13T04:48:09Z |
| publishDate | 2017-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Genetics |
| spelling | doaj.art-9e0704561f234fa09f45334b88e90a0f2022-12-22T03:01:47ZengFrontiers Media S.A.Frontiers in Genetics1664-80212017-11-01810.3389/fgene.2017.00158291245Prenatal Diagnosis of Fragile X: Can a Full Mutation Allele in the FMR1 Gene Contract to a Normal Size?Esther Manor0Esther Manor1Azhar Jabareen2Azhar Jabareen3Nurit Magal4Nurit Magal5Arei Kofman6Arei Kofman7Randi J. Hagerman8Flora Tassone9Flora Tassone10Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, IsraelGenetics Institute, Soroka Medical Center, Beersheba, IsraelFaculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, IsraelGenetics Institute, Soroka Medical Center, Beersheba, IsraelDepartment of Medical Genetics, Rabin Medical Center, Petah Tikva, IsraelFelsenstein Medical Research Center, Rabin Medical Center, Petah Tikva, IsraelFaculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, IsraelGenetics Institute, Soroka Medical Center, Beersheba, IsraelDepartment of Pediatrics, MIND Institute, UC Davis Medical Center, Sacramento, CA, United StatesDepartment of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, United StatesMIND Institute, UC Davis Medical Center, Sacramento, CA, United StatesHere we describe a case of a prenatal diagnosis of a male fetus that inherited the unstable allele from his full mutation mosaic mother (29, 160, >200 CGG repeats) reduced to a normal size range (19 CGG repeats). Haplotype analysis showed that the fetus 19 CGG repeats allele derived from the maternal unstable allele which was inherited from his maternal grandmother. No size mosaicism was detected by testing the DNA from in vitro cultured samples, including seventh passage culture as well as from two amniocentesis samples. Sequence analysis confirmed that the allele was 19 CGG repeats long. Methylation assay showed no methylation. Although none of the techniques used in this study can provide with absolute certainty the diagnosis, the results strongly indicate the presence in the fetus of an allele with a CGG repeat number in the normal range. Because this is a prenatal diagnosis case, the crucial question is whether the 19 CGG allele derived from the maternal unstable expanded allele, which contracted to the normal range, became a normal stable allele or a normal unstable allele which could expand in the next generation. It is also possible that allele size mosaicism of the FMR1 gene that went undetected exists. Because this is a prenatal diagnosis case, we cannot with certainty exclude the presence of an undetected expanded allele of the FMR1 gene, in addition to the 19 CGG allele derived from an unstable expanded allele, which contracted to the normal range.http://journal.frontiersin.org/article/10.3389/fgene.2017.00158/fullprenatal diagnosisFMR1 geneinstabilityexpansioncontraction |
| spellingShingle | Esther Manor Esther Manor Azhar Jabareen Azhar Jabareen Nurit Magal Nurit Magal Arei Kofman Arei Kofman Randi J. Hagerman Flora Tassone Flora Tassone Prenatal Diagnosis of Fragile X: Can a Full Mutation Allele in the FMR1 Gene Contract to a Normal Size? Frontiers in Genetics prenatal diagnosis FMR1 gene instability expansion contraction |
| title | Prenatal Diagnosis of Fragile X: Can a Full Mutation Allele in the FMR1 Gene Contract to a Normal Size? |
| title_full | Prenatal Diagnosis of Fragile X: Can a Full Mutation Allele in the FMR1 Gene Contract to a Normal Size? |
| title_fullStr | Prenatal Diagnosis of Fragile X: Can a Full Mutation Allele in the FMR1 Gene Contract to a Normal Size? |
| title_full_unstemmed | Prenatal Diagnosis of Fragile X: Can a Full Mutation Allele in the FMR1 Gene Contract to a Normal Size? |
| title_short | Prenatal Diagnosis of Fragile X: Can a Full Mutation Allele in the FMR1 Gene Contract to a Normal Size? |
| title_sort | prenatal diagnosis of fragile x can a full mutation allele in the fmr1 gene contract to a normal size |
| topic | prenatal diagnosis FMR1 gene instability expansion contraction |
| url | http://journal.frontiersin.org/article/10.3389/fgene.2017.00158/full |
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