13-32326497-A-T

Variant names:

• chr13-32326497-A-T
• rs81002858
• NM_000059.4:c.517-2A>T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_000059.4(BRCA2):​c.517-2A>T variant causes a splice acceptor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: BRCA2 NM_000059.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.86

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 Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.011211855 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.9, offset of 9, new splice context is: tttcctccctgggtcgtcAGaca. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32326497-A-T is Pathogenic according to our data. Variant chr13-32326497-A-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 929044.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.517-2A>T		splice_acceptor_variant, intron_variant	Intron 6 of 26	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.517-2A>T		splice_acceptor_variant, intron_variant	Intron 6 of 26	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.148-2A>T		splice_acceptor_variant, intron_variant	Intron 6 of 26	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.517-2A>T		splice_acceptor_variant, intron_variant	Intron 5 of 25	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary breast ovarian cancer syndrome Pathogenic:1

Jul 05, 2019

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: BRCA2 c.517-2A>T 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: Five predict the variant shifts a 3' acceptor site to 9 nucleotides downstream, which would create an in-frame shift. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 251306 control chromosomes. c.517-2A>T has been reported in the literature in an individual affected with Hereditary Breast and Ovarian Cancer (Sunami_2019). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	0.011	T
BayesDel_noAF	Benign	-0.22
CADD	Uncertain	25
DANN	Benign	0.96
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.98	D
GERP RS		4.3

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.85
SpliceAI score (max)		0.78		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.78		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: rs81002858; hg19: chr13-32900634;