chr17-43067617-T-C

Position:

• chr17-43067617-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PM5

The NM_007294.4(BRCA1):​c.5065A>G​(p.Met1689Val) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M1689R) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 30)
• Consequence: BRCA1 NM_007294.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3 O:1
• Conservation: PhyloP100: 4.79

Genes affected

BRCA1 (HGNC:1100): (BRCA1 DNA repair associated) This gene encodes a 190 kD nuclear phosphoprotein that plays a role in maintaining genomic stability, and it also acts as a tumor suppressor. The BRCA1 gene contains 22 exons spanning about 110 kb of DNA. The encoded protein combines with other tumor suppressors, DNA damage sensors, and signal transducers to form a large multi-subunit protein complex known as the BRCA1-associated genome surveillance complex (BASC). This gene product associates with RNA polymerase II, and through the C-terminal domain, also interacts with histone deacetylase complexes. This protein thus plays a role in transcription, DNA repair of double-stranded breaks, and recombination. Mutations in this gene are responsible for approximately 40% of inherited breast cancers and more than 80% of inherited breast and ovarian cancers. Alternative splicing plays a role in modulating the subcellular localization and physiological function of this gene. Many alternatively spliced transcript variants, some of which are disease-associated mutations, have been described for this gene, but the full-length natures of only some of these variants has been described. A related pseudogene, which is also located on chromosome 17, has been identified. [provided by RefSeq, May 2020]

BRCA1 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a strand (size 3) in uniprot entity BRCA1_HUMAN there are 6 pathogenic changes around while only 1 benign (86%) in NM_007294.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-43067616-A-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.5065A>G	p.Met1689Val	missense_variant	16/23	ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.5065A>G	p.Met1689Val	missense_variant	16/23	1	NM_007294.4	ENSP00000350283.3

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 30

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	May 16, 2016	The p.M1689V variant (also known as c.5065A>G), located in coding exon 15 of the BRCA1 gene, results from an A to G substitution at nucleotide position 5065. The methionine at codon 1689 is replaced by valine, an amino acid with highly similar properties. A similar alteration at the same codon, p.M1689R (c.5066T>G), has been shown to segregate with disease in a large 3-generation family and lead to a loss-of-function phenotype in both yeast and mammalian transcription assays (Mirkovic N, et al. Cancer Res. 2004 Jun; 64(11):3790-7). This similar alteration has also been classified as likely pathogenic (p>0.9889) by multifactorial analysis, which integrates the following lines of evidence to produce a quantitative likelihood of pathogenicity: in silico prediction models, segregation with disease, tumor characteristics, mutation co-occurrence, and functional assay results (Easton D et al. Am J Hum Genet. 2007;81:873-883; Lindor NM, et al. Hum. Mutat. 2012 Jan; 33(1):8-21). The p.M1689V variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6502 samples (13004 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.0004% (greater than 225000 alleles tested) in our clinical cohort. This amino acid position is well 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	Jun 16, 2019	- -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 08, 2017

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. A different missense substitution at this codon (p.Met1689Arg) has been determined to be pathogenic (PMID: 20516115, 15172985, 27272900, 15172985, 17924331). This suggests that the methionine residue is critical for BRCA1 protein function and that other missense substitutions at this position may also be pathogenic. This variant has not been reported in the literature in individuals with BRCA1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency). This sequence change replaces methionine with valine at codon 1689 of the BRCA1 protein (p.Met1689Val). The methionine residue is highly conserved and there is a small physicochemical difference between methionine and valine. -

Breast-ovarian cancer, familial, susceptibility to, 1 Other:1

not provided, no classification provided

in vitro

Brotman Baty Institute, University of Washington

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.010
CADD	Benign	22
DANN	Uncertain	0.98
DEOGEN2	Benign	0.12	.;T;.;.;T;.;.;.;T;.
Eigen	Uncertain	0.29
Eigen_PC	Uncertain	0.37
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.92	D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.38	D
MetaRNN	Uncertain	0.60	D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.14	T
MutationAssessor	Benign	1.7	.;L;.;.;.;.;.;.;.;.
PrimateAI	Uncertain	0.66	T
PROVEAN	Benign	-2.2	N;N;.;D;.;N;N;D;N;D
REVEL	Uncertain	0.50
Sift	Benign	0.28	T;D;.;T;.;D;T;T;T;T
Sift4G	Uncertain	0.025	D;D;D;D;D;D;D;.;.;D
Polyphen		0.085, 0.78	.;B;.;.;.;.;.;.;P;.
Vest4		0.67
MVP		0.94
MPC		0.12
ClinPred		0.81	D
GERP RS		5.2
Varity_R		0.71
gMVP		0.64

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1555579619; hg19: chr17-41219634;