Journal of Clinical Case Reports

De Novo BRCA1 Pathogenic Variant in a Woman with Breast Cancer at Age 33: A Case Report

Abstract

Tam S, Vesprini D, Eisen A and Lorentz J

BRCA1 and BRCA2 are tumor suppressor genes that aid in non-homologous DNA repair. Germline pathogenic variants in these genes cause hereditary breast and ovarian cancer syndrome (HBOC). De novo pathogenic variants (PVs) in BRCA1 and BRCA2 are rare. In the literature, to date, twelve BRCA1 (including the present) and six BRCA2 de novo PVs have been published. We present a woman of Scottish and English descent, with a de novo BRCA1 likely pathogenic variant (LPV) diagnosed with triple negative breast cancer at age 33. The patient was referred for genetic counseling. Neither of her parents carried this familial variant and parental inheritance testing was done to rule-out a non-paternity or non-maternity event. A de novo LPV is the most plausible explanation for this case. Knowing whether there is a BRCA1 or BRCA2 PV is of significant clinical value in breast and ovarian cancer prevention and management. Knowledge of the rate of de novo PVs provides additional information to practicing geneticists and genetic counselors to aid in pedigree assessment for the HBOC in families.