13-32316529-T-C

Position:

• chr13-32316529-T-C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000059.4(BRCA2):​c.67+2T>C variant causes a splice donor change. The variant allele was found at a frequency of 0.00000205 in 1,460,612 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BRCA2 NM_000059.4 splice_donor
• Scores: Splicing: ADA: 0.9947
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:11
• Conservation: PhyloP100: 4.35

Genes affected

BRCA2 (HGNC:1101): (BRCA2 DNA repair associated) Inherited mutations in BRCA1 and this gene, BRCA2, confer increased lifetime risk of developing breast or ovarian cancer. Both BRCA1 and BRCA2 are involved in maintenance of genome stability, specifically the homologous recombination pathway for double-strand DNA repair. The largest exon in both genes is exon 11, which harbors the most important and frequent mutations in breast cancer patients. The BRCA2 gene was found on chromosome 13q12.3 in human. The BRCA2 protein contains several copies of a 70 aa motif called the BRC motif, and these motifs mediate binding to the RAD51 recombinase which functions in DNA repair. BRCA2 is considered a tumor suppressor gene, as tumors with BRCA2 mutations generally exhibit loss of heterozygosity (LOH) of the wild-type allele. [provided by RefSeq, May 2020]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32316529-T-C is Pathogenic according to our data. Variant chr13-32316529-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 52163.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr13-32316529-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.67+2T>C		splice_donor_variant		ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.67+2T>C		splice_donor_variant		5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250582 Hom.: 0 AF XY: 0.00000738 AC XY: 1 AN XY: 135566

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000883

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1460612 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726674

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:11

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 2 Pathogenic:6

Pathogenic, criteria provided, single submitter	clinical testing	Genologica Medica	Jan 01, 2017	- -
Pathogenic, no assertion criteria provided	clinical testing	Breast Cancer Information Core (BIC) (BRCA2)	Feb 20, 2004	- -
Pathogenic, criteria provided, single submitter	clinical testing;provider interpretation	Geisinger Autism and Developmental Medicine Institute, Geisinger Health System	Oct 04, 2017	This variant was identified in a 3 year old male with autism spectrum disorder, global developmental delay, hypotonia, and plagiocephaly, as a secondary finding. It was inherited from a healthy father who's family history includes several females with breast cancer. This variant has been reported in the literature and in ClinVar as a pathogenic variant, due to association with hereditary breast/ovarian cancer. The variant alters a canonical splice site. -
Pathogenic, criteria provided, single submitter	clinical testing	Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), c/o University of Cambridge	Oct 02, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	KCCC/NGS Laboratory, Kuwait Cancer Control Center	Jun 06, 2023	A known pathogenic mutation was detected in the BRCA2 gene (c.67+2T>C). This sequence change affects a donor splice site in intron 2 of the BRCA2 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. This variant is not present in population databases (gnomAD). This variant has been reported in an individual and a family affected with breast/ovarian cancer (PMID: 12955716, 22798144). This variant is also known as IVS2+2T>C and 295+2T>C in the literature. ClinVar contains an entry for this variant (Variation ID: 52163). Experimental studies have shown that this intronic change disrupts splicing and results in an mRNA product with exon 2 skipped (PMID: 22505045). Exon 2 contains the translational start site of BRCA2. Loss-of-function variants in BRCA2 are known to be pathogenic (PMID: 20104584). Therefore, this variant has been classified as Pathogenic. This variant was confirmed by Sanger sequencing . -
Pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Oct 27, 2016	- -

Hereditary breast ovarian cancer syndrome Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Nov 03, 2022	The c.67+2T>C variant in BRCA2 has been reported in at least 7 individuals affected with Hereditary Breast and Ovarian Cancer (selected references, Diez 2003 PMID: 12955716, Al Hannan 2019 PMID: 31131559, Rebbeck 2018 PMID: 29446198, Pajares 2018 PMID: 29884136). It has also been reported in ClinVar (Variation ID 52163) but was absent from large population studies. This variant occurs within the canonical splice site (+/- 1,2) and is predicted to cause altered splicing leading to an abnormal or absent protein. In vitro functional studies provide some evidence that this variant affects mRNA splicing (Houdayer 2012 PMID: 22505045, Fraile-Bethencourt 2019 PMID: 30883759). Loss of function of the BRCA2 gene is an established disease mechanism in autosomal dominant hereditary breast and ovarian cancer syndrome. In summary, this variant meets criteria to be classified as pathogenic for autosomal dominant hereditary breast and ovarian cancer syndrome. ACMG/AMP Criteria applied: PM2_supporting, PVS1, PS4_Moderate. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 23, 2020	Variant summary: BRCA2 c.67+2T>C is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a canonical 5' splicing donor site. At least one publication reports experimental evidence that this variant affects mRNA splicing (Houdayer_2012). The variant allele was found at a frequency of 4e-06 in 250582 control chromosomes. c.67+2T>C has been reported in the literature in individuals affected with Hereditary Breast and Ovarian Cancer (example, Diez_2003, AlHannan_2019, Rebbeck_2018). These data indicate that the variant is likely to be associated with disease. Five clinical diagnostic laboratories and one consortium (CIMBA) have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All submitters classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	May 30, 2023	For these reasons, this variant has been classified as Pathogenic. Studies have shown that disruption of this splice site alters mRNA splicing and is expected to lead to the loss of protein expression (PMID: 17011978, 22505045, 30883759). ClinVar contains an entry for this variant (Variation ID: 52163). This variant is also known as IVS2+2T>C and 295+2T>C. Disruption of this splice site has been observed in individual(s) with breast and/or ovarian cancer and/or breast cancer (PMID: 12955716, 21063910, 22798144). It has also been observed to segregate with disease in related individuals. This variant is present in population databases (rs81002885, gnomAD 0.0009%). This sequence change affects a donor splice site in intron 2 of the BRCA2 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or disrupted protein product. -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Oct 11, 2018	The variant disrupts a canonical splice site, and is therefore predicted to significantly disrupt the protein structure. Found in at least one symptomatic patient, and found in general population data that is consistent with pathogenicity. -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jun 22, 2023	Published functional studies demonstrate a damaging effect: results in exon 2 skipping which contains the initiator codon, unable to rescue cell viability in a complementation assay (Houdayer et al., 2012; Fraile-Bethencourt et al., 2019; Mesman et al., 2020); Observed in individuals with a personal or family history consistent with pathogenic variants in this gene (Diez et al., 2003; Martinez-Ferrandis et al., 2003; Kim et al., 2012; Pajares et al., 2018; Al Hannan et al., 2019); Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Also known as 295+2T>C; This variant is associated with the following publications: (PMID: 31131967, 29446198, 31131559, 14517958, 25525159, 22798144, 22505045, 12955716, 18528753, 30720243, 29884136, 33654310, 32398771, 30883759) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Pathogenic	28
DANN	Uncertain	0.99
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Uncertain	0.86	D
MutationTaster	Benign	1.0	D;D
GERP RS		5.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Benign	0.65
SpliceAI score (max)		0.94		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.94		Position offset: -2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs81002885; hg19: chr13-32890666;