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2023 ACMG Annual Clinical Genetics Meeting Digital ...
Mosaic Li Fraumeni Syndrome Identified in Patient ...
Mosaic Li Fraumeni Syndrome Identified in Patient with a Previously Presumed Germline Variant Following Preimplantation Genetic Testing: A Case Report
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This case report discusses a patient who was initially diagnosed with a presumed germline variant but was later identified to have mosaic Li Fraumeni syndrome (LFS) following preimplantation genetic testing. LFS is a hereditary cancer syndrome caused by pathogenic alterations of the TP53 gene. The patient had a history of adrenocortical neoplasm and osteosarcoma at a young age. Immunohistochemistry staining of the patient's tumors showed positive p53 expression. Initial next-generation sequencing (NGS) testing on peripheral blood identified a pathogenic TP53 variant, which was presumed germline based on the variant allele frequency and the patient's oncologic history. However, follow-up testing using NGS on various tissue types, including a new peripheral blood sample, revealed mosaic LFS instead of clonal hematopoiesis of indeterminate potential (CHIP). These results suggest a post-zygotic event consistent with mosaic LFS. The patient can still follow the surveillance guidelines for classic LFS, including regular imaging, colonoscopy, and dermatologic exams. This case highlights the complexity of interpreting mosaic TP53 variants and the challenges in providing cancer and reproductive risk information in the context of mosaicism.
Asset Subtitle
Co-Author - Rhianna Urban, MS, CGC; Presenting Author - Megan Holdren, MS, CGC; Co-Author - Megan Hoenig, MS, MPH, CGC; Co-Author - Laura M. Rust, MS, CGC; Co-Author - Myra J. Wick, MD, PhD, FACMG; Co-Author - Matthew Ferber, PhD; Co-Author - Zhiyv Niu, PhD; Co-Author - Sounak Gupta, MBBS, PhD; Co-Author - Wei Shen, PhD;
Meta Tag
Cancer Syndromes
Counseling
Genetic Testing
Co-Author
Rhianna Urban, MS, CGC
Co-Author
Megan Hoenig, MS, MPH, CGC
Co-Author
Laura M. Rust, MS, CGC
Co-Author
Myra J. Wick, MD, PhD, FACMG
Co-Author
Matthew Ferber, PhD
Co-Author
Zhiyv Niu, PhD
Co-Author
Sounak Gupta, MBBS, PhD
Co-Author
Wei Shen, PhD
Presenting Author
Megan Holdren, MS, CGC
Keywords
germline variant
mosaic Li Fraumeni syndrome
preimplantation genetic testing
TP53 gene
adrenocortical neoplasm
osteosarcoma
immunohistochemistry staining
next-generation sequencing
clonal hematopoiesis of indeterminate potential
mosaicism
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