Low allele fraction, high stakes: Discerning germline mosaic TP53 variants from clonal hematopoiesis of indeterminate potential (CHIP)

Presenting Author: Magan Trottier, MS, CGC

Take home point: 

• When a TP53 likely pathogenic/pathogenic variant is detected at a low allele fraction, this presents a diagnostic challenge: these findings may represent germline mosaic Li-Fraumeni syndrome or incidentally detected clonal hematopoiesis of indeterminate potential (CHIP), which carry different risks and have different management recommendations for patients and families. We are analyzing characteristics, including presence of genes commonly altered in CHIP, that may help discern between mosaic Li-Fraumeni syndrome and CHIP.