BRCA2 c.156_157insAlu Founder Variant in Northern Portugal: An Insight Into Hereditary Breast and Ovarian Cancer
Sílvia A C Duarte1,2, Regina Arantes3, Márcia Martins4
1Medical Oncology Department, Local Health Unit Trás-os-Montes and Alto Douro, Vila Real, Portugal.
None:
The BRCA2 c.156_157insAlu variant is a Portuguese founder mutation implicated in hereditary breast and ovarian cancer (HBOC). This study aims to determine its occurrence and clinical implications in the northern interior region of Portugal. A retrospective study of 571 individuals referred for HBOC genetic counseling and testing between 2021 and 2024 was conducted. Genetic screening was performed using next-generation sequencing of 27 hereditary cancer genes, with confirmatory PCR for BRCA2 c.156_157insAlu. Pathogenic or likely pathogenic variants were detected in 19.8% of participants, with BRCA1/2 variants accounting for 5.4%. The BRCA2 c.156_157insAlu variant was identified in 6 individuals (25% of all BRCA2 pathogenic variants identified), including breast cancer patients and asymptomatic carriers. Clinically, it was associated with early onset and contralateral breast cancer. Cascade testing and genetic counseling were offered to at-risk relatives. The BRCA2 c.156_157insAlu variant remains a significant contributor to HBOC in northern Portugal. Its high local proportion among BRCA2 variants supports the implementation of targeted genetic testing strategies, enhancing early detection and personalized cancer risk management.
Related Concept Videos
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,...
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...
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...
The Ras Gene
Ras is a...
Cancers Originate from Somatic Mutations in a Single Cell
Human Genetics
The complex relationship between genetics and psychology is observable through common biological components such...


