The BRCA2 genetic variant IVS7 + 2T-->G is a mutation

Area of Science:

• Genetics
• Molecular Biology
• Oncology

Background:

• The BRCA2 gene plays a crucial role in DNA repair and tumor suppression.
• Mutations in BRCA2 are associated with an increased risk of hereditary breast and ovarian cancers.
• Understanding the functional impact of specific BRCA2 variants is essential for genetic counseling and risk assessment.

Purpose of the Study:

• To biochemically and genetically characterize the BRCA2 IVS7 + 2T --> G variant.
• To determine if this intronic variant represents a deleterious mutation.
• To elucidate the molecular mechanism by which this variant affects BRCA2 mRNA processing.

Main Methods:

• RNA analysis was performed on a breast cancer patient carrying the BRCA2 IVS7 + 2T --> G variant.
• Haplotype analysis was used to track the variant's location on the chromosome.
• A coding region polymorphism served as a marker to differentiate allelic contributions to RNA species.
• Single nucleotide polymorphism (SNP) haplotype analysis was employed to confirm variant localization.

Main Results:

• The BRCA2 IVS7 + 2T --> G variant was found to reside on the chromosome that does not produce normal mRNA.
• RNA analysis revealed the production of a splicing product that deletes exon 7 from the affected chromosome.
• This exon 7 deletion alters the open reading frame, leading to premature termination of translation.
• The study successfully tracked the contribution of both chromosomes to RNA species, confirming the variant's impact.

Conclusions:

• The BRCA2 IVS7 + 2T --> G variant is a deleterious mutation.
• This mutation leads to aberrant mRNA splicing, resulting in a non-functional BRCA2 protein.
• The findings provide strong evidence for the pathogenic nature of this variant and its association with cancer predisposition.