RESUMO
BACKGROUND: The incidence of breast cancer is growing rapidly worldwide (1.7 million new cases and 600,000 deaths per year). Moreover, about 10% of breast cancer cases occur in young women under the age of 45. The aim of the study was to report a rare case of BRCA 1-mutated breast cancer in a young patient with multiple affected relatives. Breast cancer is due to a genetic predisposition with BRCA1 and BRCA2 representing a significant proportion of families with a very high risk of developing the disease over a lifetime of up to 50-80%. CASE PRESENTATION: In this paper we report a case of a 29-year-old woman with a confirmed diagnosis of left breast carcinoma. CONCLUSIONS: Mutations of the BRCA1 gene were revealed in the patient, in two of her sisters, brother and brother's daughter.