Assessing the Clinical Relevance of BRCA1 RING Domain Variants of Uncertain Significance

Area of Science:

• Genetics and Genomics
• Cancer Biology
• Bioinformatics

Background:

• Pathogenic BRCA1 variants significantly increase breast cancer (BC) risk.
• Variants of uncertain significance (VUSs) hinder genetic screening and clinical decisions.
• The BRCA1 RING domain is crucial for genomic integrity and a focus for VUS analysis.

Purpose of the Study:

• To reclassify BRCA1 VUSs using computational and functional evidence.
• To specifically analyze missense variants within the BRCA1 RING domain.
• To improve clinical decision-making for individuals with BRCA1 VUSs.

Main Methods:

• Developed a six-feature linear support vector machine (LSVM) for BRCA1 RING variants.
• Utilized mammalian cell co-immunoprecipitation (co-IP) to quantify BRCA1-BARD1 binding.
• Correlated LSVM and co-IP results with a homology-directed repair (HDR) assay.

Main Results:

• The LSVM achieved 84% accuracy in predicting in vitro binding loss for BRCA1 RING variants.
• Computational and functional assays provided evidence for 322 VUSs.
• Three VUSs (N16S, A17D, E100D) were reclassified as likely benign, and one (H41P) as likely pathogenic.

Conclusions:

• Domain-specific VUS reclassification is effective for BRCA1.
• Accurate VUS classification improves breast cancer risk assessment and patient management.
• This approach enhances the utility of genetic testing for hereditary breast cancer.