2023 ACMG Annual Clinical Genetics Meeting Digital Edition: Poster Gallery-Four Cases of Mosaic Triploidy Identified by Trio Exome Sequencing

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In a study conducted by GeneDx, four cases of mosaic triploidy were detected using trio exome sequencing. The detection rate of mosaic triploidy was found to be 34 times higher than what has been reported in the literature. Mosaic triploidy is a rare form of mosaicism associated with a malformation syndrome. It is characterized by the presence of an additional cell line that contains three sets of chromosomes instead of the normal two. Detection of mosaic triploidy can be challenging and many cases may go undiagnosed. However, the use of trio exome sequencing has proven helpful in identifying this condition.<br /><br />The study also found that trio exome sequencing can provide a diagnosis for cases that were previously undetermined. In one case, prior cytogenetic studies and NGS panel testing yielded negative results, but trio exome sequencing was able to detect mosaic triploidy. The study suggests that skin biopsy samples are commonly used for detecting mosaic triploidy, but oral buccal and amniotic fluid samples can also be useful.<br /><br />The detection and confirmation of mosaic triploidy in the study were performed using allele balance analysis and STR analysis of highly polymorphic markers. Follow-up FISH analysis on cultured fibroblasts confirmed the presence of the triploid cell line.<br /><br />Overall, the study demonstrates the effectiveness of trio exome sequencing in detecting mosaic triploidy and suggests that many cases may go undiagnosed using other methods. The findings contribute to the understanding of this rare condition and provide valuable information for improving diagnostic approaches.

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Co-Author - Wei Wang, PhD; Co-Author - Lindsay B. Henderson, PhD, FACMG; Co-Author - Julie Scuffins, MS; Co-Author - Lisa M. Dyer, PhD; Co-Author - Lindsay Havens Dyer, BS; Co-Author - Ganka V. Douglas, PhD; Co-Author - Kristin G. Monaghan, PhD; Co-Author - Michelle Morrow, MS, PhD; Presenting Author - Ludmila Matyakhina, PhD;

Meta Tag

Chromosomal Abnormalities

Clinical Applications of Molecular Cytogenetics

Clinical Cytogenetics

Cytogenetics

Exome sequencing

Genetic Testing

Molecular Cytogenetics

NextGen Sequencing

Sequencing

Co-Author Wei Wang, PhD

Co-Author Lindsay B. Henderson, PhD, FACMG

Co-Author Julie Scuffins, MS

Co-Author Lisa M. Dyer, PhD

Co-Author Lindsay Havens Dyer, BS

Co-Author Ganka V. Douglas, PhD

Co-Author Kristin G. Monaghan, PhD

Co-Author Michelle Morrow, MS, PhD

Presenting Author Ludmila Matyakhina, PhD

Keywords

GeneDx

mosaic triploidy

trio exome sequencing

detection rate

literature

malformation syndrome

mosaicism

chromosomes

undiagnosed cases

allele balance analysis