Next Article in Journal
ALDH2 p.E504K Variation and Sex Are Major Factors Associated with Current and Quitting Alcohol Drinking in Japanese Oldest Old
Previous Article in Journal
CRISPR-Based Genome Editing Tools: Insights into Technological Breakthroughs and Future Challenges
Case Report

Detection of Cryptic Fragile X Full Mutation Alleles by Southern Blot in a Female and Her Foetal DNA via Chorionic Villus Sampling, Complicated by Mosaicism for 45,X0/46,XX/47,XXX

1
Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
2
Maternal Fetal Medicine Department, Royal Hospital for Women, Randwick, NSW 2031, Australia
3
Centre for Clinical Genetics, Sydney Children’s Hospital, Randwick, NSW 2031, Australia
4
Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
5
Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC 3052, Australia
*
Author to whom correspondence should be addressed.
Academic Editor: Giovanni Neri
Genes 2021, 12(6), 798; https://doi.org/10.3390/genes12060798
Received: 8 April 2021 / Revised: 8 May 2021 / Accepted: 18 May 2021 / Published: 24 May 2021
(This article belongs to the Special Issue Fragile X Syndrome Genetics)
We describe a female with a 72 CGG FMR1 premutation (PM) (CGG 55–199) and family history of fragile X syndrome (FXS), referred for prenatal testing. The proband had a high risk of having an affected pregnancy with a full mutation allele (FM) (CGG > 200), that causes FXS through hypermethylation of the FMR1 promoter. The CGG sizing analysis in this study used AmplideX triplet repeat primed polymerase chain reaction (TP-PCR) and long-range methylation sensitive PCR (mPCR). These methods detected a 73 CGG PM allele in the proband’s blood, and a 164 CGG PM allele in her male cultured chorionic villus sample (CVS). In contrast, the Southern blot analysis showed mosaicism for: (i) a PM (71 CGG) and an FM (285–768 CGG) in the proband’s blood, and (ii) a PM (165 CGG) and an FM (408–625 CGG) in the male CVS. The FMR1 methylation analysis, using an EpiTYPER system in the proband, showed levels in the range observed for mosaic Turner syndrome. This was confirmed by molecular and cytogenetic karyotyping, identifying 45,X0/46,XX/47,XXX lines. In conclusion, this case highlights the importance of Southern blot in pre- and postnatal testing for presence of an FM, which was not detected using AmplideX TP-PCR or mPCR in the proband and her CVS. View Full-Text
Keywords: fragile; X syndrome; FMR1; mosaicism; CGG; cultured chorionic villus; sample; southern blot; full mutation; 45,X0/46,XX/47,XXX fragile; X syndrome; FMR1; mosaicism; CGG; cultured chorionic villus; sample; southern blot; full mutation; 45,X0/46,XX/47,XXX
Show Figures

Figure 1

MDPI and ACS Style

Pandelache, A.; Francis, D.; Oertel, R.; Dickson, R.; Sachdev, R.; Ling, L.; Gamage, D.; Godler, D.E. Detection of Cryptic Fragile X Full Mutation Alleles by Southern Blot in a Female and Her Foetal DNA via Chorionic Villus Sampling, Complicated by Mosaicism for 45,X0/46,XX/47,XXX. Genes 2021, 12, 798. https://doi.org/10.3390/genes12060798

AMA Style

Pandelache A, Francis D, Oertel R, Dickson R, Sachdev R, Ling L, Gamage D, Godler DE. Detection of Cryptic Fragile X Full Mutation Alleles by Southern Blot in a Female and Her Foetal DNA via Chorionic Villus Sampling, Complicated by Mosaicism for 45,X0/46,XX/47,XXX. Genes. 2021; 12(6):798. https://doi.org/10.3390/genes12060798

Chicago/Turabian Style

Pandelache, Alison, David Francis, Ralph Oertel, Rebecca Dickson, Rani Sachdev, Ling Ling, Dinusha Gamage, and David E. Godler 2021. "Detection of Cryptic Fragile X Full Mutation Alleles by Southern Blot in a Female and Her Foetal DNA via Chorionic Villus Sampling, Complicated by Mosaicism for 45,X0/46,XX/47,XXX" Genes 12, no. 6: 798. https://doi.org/10.3390/genes12060798

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop