Related Experiment Video
Updated: Jul 12, 2025

Functional Assessment of BRCA1 variants using CRISPR-Mediated Base Editors
Published on: February 28, 2021
A de Novo BRCA1 Pathogenic Variant in a 29-Year-Old Woman with Triple-Negative Breast Cancer
Paulina Gebhart1, Yen Tan1, Daniela Muhr1
1Department of Obstetrics and Gynecology, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
Introduction:
Germline pathogenic variants in the BRCA1 and BRCA2 genes lead to a highly increased lifetime risk for breast and ovarian cancer. These variants are usually inherited and reports of de novo occurrences are a very rare phenomenon.
Case Presentation:
We report on a breast cancer patient with a de novo BRCA1 variant c.121C>T (p.His41Tyr). The pathogenic variant was detected in leukocyte DNA of a patient with negative family history who had developed early onset, triple-negative breast cancer. The variant was not found in any of the maternal and paternal tissues tested, but it was detected in multiple samples representing all three germ layers of the affected carrier, which renders somatic mosaicism unlikely.
Conclusion:
This case highlights the importance of including early onset of disease and triple negativity of the tumor as criteria for genetic testing, even in patients without family history. Considering the availability of effective breast cancer treatments in patients with pathogenic variants in the BRCA genes, this finding underscores the importance of genetic testing in breast cancer patients.
More Related Videos
08:15gDNA Enrichment by a Transposase-based Technology for NGS Analysis of the Whole Sequence of BRCA1, BRCA2, and 9 Genes Involved in DNA Damage Repair
Published on: October 6, 2014
08:53Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1
Published on: February 17, 2011
Related Concept Videos
Cancers Originate from Somatic Mutations in a Single Cell
Rous Sarcoma Virus (RSV) and Cancer
RSV is a retrovirus that contains two copies of a plus-strand RNA genome. Its genome consists of four main open...
Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
The Retinoblastoma Gene
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
Cancer-Critical Genes I: Proto-oncogenes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...