Clinical, splicing, and functional analysis to classify BRCA2 exon 3 variants: Application of a points-based ACMG/AMP approach
Document Type
Article
Publication Date
12-1-2022
Abstract
Skipping of BRCA2 exon 3 ( increment E3) is a naturally occurring splicing event, complicating clinical classification of variants that may alter increment E3 expression. This study used multiple evidence types to assess pathogenicity of 85 variants in/near BRCA2 exon 3. Bioinformatically predicted spliceogenic variants underwent mRNA splicing analysis using minigenes and/or patient samples. increment E3 was measured using quantitative analysis. A mouse embryonic stem cell (mESC) based assay was used to determine the impact of 18 variants on mRNA splicing and protein function. For each variant, population frequency, bioinformatic predictions, clinical data, and existing mRNA splicing and functional results were collated. Variant class was assigned using a gene-specific adaptation of ACMG/AMP guidelines, following a recently proposed points-based system. mRNA and mESC analysis combined identified six variants with transcript and/or functional profiles interpreted as loss of function. Cryptic splice site use for acceptor site variants generated a transcript encoding a shorter protein that retains activity. Overall, 69/85 (81%) variants were classified using the points-based approach. Our analysis shows the value of applying gene-specific ACMG/AMP guidelines using a points-based approach and highlights the consideration of cryptic splice site usage to appropriately assign PVS1 code strength.
Keywords
ACMG, AMP classification, BRCA2, dPCR, functional analysis, quantitation, splicing
Corp List
ENIGMA Consortium
Divisions
surgerydept
Funders
Italian Ministry of Health; Den Norske Kreftforening,Spanish Health Research Foundation,NIHR Research Professorship,Ministry of Health of the Czech Republic MH CZ - DRO,Federal Ministry of Education & Research (BMBF)
Publication Title
HUMAN MUTATION
Volume
43
Issue
12
Publisher
WILEY-HINDAWI
Publisher Location
ADAM HOUSE, 3RD FL, 1 FITZROY SQ, LONDON, WIT 5HE, ENGLAND