13-32326533-T-C

Position:

• chr13-32326533-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000059.4(BRCA2):​c.551T>C​(p.Leu184Pro) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,461,618 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. L184L) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8 B:2
• Conservation: PhyloP100: 5.38

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 Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.551T>C	p.Leu184Pro	missense_variant	7/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.551T>C	p.Leu184Pro	missense_variant	7/27	5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461618 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727118

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000756

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:8 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 2 Uncertain:3 Benign:1

Uncertain significance, no assertion criteria provided	clinical testing	Breast Cancer Information Core (BIC) (BRCA2)	-	- -
Likely benign, no assertion criteria provided	clinical testing	Sharing Clinical Reports Project (SCRP)	Oct 24, 2012	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Jan 27, 2016	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Sep 20, 2017	- -

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jan 20, 2023	The p.L184P variant (also known as c.551T>C), located in coding exon 6 of the BRCA2 gene, results from a T to C substitution at nucleotide position 551. The leucine at codon 184 is replaced by proline, an amino acid with similar properties. This alteration was observed in 3/830 Japanese patients who underwent genetic testing for BRCA1 and BRCA2 (Arai M et al. J. Hum. Genet. 2018 Apr;63:447-457). It has been identified in a Japanese patient with ovarian cancer, as well as a Japanese patient with pancreatic ductal adenocarcinoma (Sekine M et al. Clin. Cancer Res. 2001 Oct;7(10):3144-50; Takeuchi S et al. Sci Rep. 2018 05;8:8105). This alteration has been reported with a carrier frequency of 0.00057 in 7,051 unselected female breast cancer patients as well as 0.00027 in 11,241 female controls and 0.0002 in 12,490 male controls of Japanese ancestry (Momozawa Y et al. Nat Commun. 2018 10;9:4083). This alteration has also been reported with a carrier frequency of 0.00052 in 7,636 unselected prostate cancer patients and 0.00024 in 12,366 male controls of Japanese ancestry (Momozawa Y et al. J Natl Cancer Inst, 2020 Apr;112:369-376). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	May 01, 2019	- -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Jun 13, 2022

Variant summary: BRCA2 c.551T>C (p.Leu184Pro) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251408 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.551T>C has been reported in the literature in individuals affected with Breast and/or Ovarian Cancer and pancreatic cancer (example: Arai_2018, Sekine_2001, Takeuchi_2018 and Momozawa_2018) and unaffected controls (Momozawa_2018). These reports do not provide unequivocal conclusions about association of the variant with Hereditary Breast And Ovarian Cancer Syndrome. Using a minigene assay Di Giacomo_2013 demonstrated this variant does not lead to exon skipping. Six clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as VUS (n=5) and likely benign (n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Sep 19, 2018

This variant is denoted BRCA2 c.551T>C at the cDNA level, p.Leu184Pro (L184P) at the protein level, and results in the change of a Leucine to a Proline (CTA>CCA). Using alternate nomenclature, this variant would be defined as BRCA2 779T>C. This variant was observed in a Japanese woman with epithelial ovarian cancer, in three other Japanese individuals referred for BRCA1/2 testing, and in an individual with pancreatic cancer (Sekine 2001, Arai 2017, Takeuchi 2018). This variant was reported to not increase exon skipping in a minigene reporter assay (Di Giacomo 2013). BRCA2 Leu184Pro was not observed in large population cohorts (Lek 2016). This variant is not located in a known functional domain. In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function. Based on currently available evidence, it is unclear whether BRCA2 Leu184Pro is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Dec 05, 2023

- -

Hereditary breast ovarian cancer syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 16, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Uncertain	0.066	T
BayesDel_noAF	Benign	-0.14
CADD	Pathogenic	26
DANN	Pathogenic	1.0
Eigen	Uncertain	0.42
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Pathogenic	0.47	D
MetaRNN	Uncertain	0.60	D;D
MetaSVM	Benign	-1.2	T
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-1.8	N;N
REVEL	Benign	0.26
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.0020	D;D
Vest4		0.55
MutPred		0.32		Loss of stability (P = 0.0145);Loss of stability (P = 0.0145);
MVP		0.92
MPC		0.19
ClinPred		0.95	D
GERP RS		5.5
gMVP		0.81

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs80358775; hg19: chr13-32900670;