chr13-32336621-C-T

Position:

• chr13-32336621-C-T

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.2266C>T​(p.Gln756Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA2 NM_000059.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:5
• Conservation: PhyloP100: 1.11

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: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32336621-C-T is Pathogenic according to our data. Variant chr13-32336621-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 373824.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr13-32336621-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.2266C>T	p.Gln756Ter	stop_gained	11/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.2266C>T	p.Gln756Ter	stop_gained	11/27	5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: reviewed by expert panel

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 2 Pathogenic:1

Pathogenic, reviewed by expert panel

curation

Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA)

Dec 15, 2017

Variant allele predicted to encode a truncated non-functional protein. -

Breast neoplasm Pathogenic:1

Pathogenic, criteria provided, single submitter

research

A.C.Camargo Cancer Center / LGBM, A.C.Camargo Cancer Center

-

- -

Malignant tumor of urinary bladder Pathogenic:1

Pathogenic, no assertion criteria provided

research

Laboratory of Urology, Hospital Clinic de Barcelona

-

- -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 16, 2017

The p.Q756* pathogenic mutation (also known as c.2266C>T), located in coding exon 10 of the BRCA2 gene, results from a C to T substitution at nucleotide position 2266. This changes the amino acid from a glutamine to a stop codon within coding exon 10. This alteration, designated 2494C>T, has been previously reported in a Brazilian patient diagnosed with breast cancer at age 24 who also had a family history consistent with hereditary breast and ovarian cancer (HBOC) syndrome (Carraro DM et al. PLoS ONE. 2013 Mar;8:e57581). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Hereditary breast ovarian cancer syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 14, 2023

This sequence change creates a premature translational stop signal (p.Gln756*) in the BRCA2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BRCA2 are known to be pathogenic (PMID: 20104584). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with breast cancer (PMID: 23469205, 29161300, 29907814). ClinVar contains an entry for this variant (Variation ID: 373824). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	33
DANN	Uncertain	1.0
Eigen	Uncertain	0.23
Eigen_PC	Benign	-0.055
FATHMM_MKL	Benign	0.074	N
MutationTaster	Benign	1.0	A;A
Vest4		0.88
GERP RS		3.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs1057518637; hg19: chr13-32910758;