rs587781771

Positions:

• chr17-43092852-C-A
• chr17-43092852-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_007294.4(BRCA1):​c.2679G>T​(p.Lys893Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,672 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BRCA1 NM_007294.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: -0.283

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 Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.1737265).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.2679G>T	p.Lys893Asn	missense_variant	10/23	ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.2679G>T	p.Lys893Asn	missense_variant	10/23	1	NM_007294.4	ENSP00000350283.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461672 Hom.: 0 Cov.: 50 AF XY: 0.00 AC XY: 0 AN XY: 727126

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Likely benign, criteria provided, single submitter	curation	University of Washington Department of Laboratory Medicine, University of Washington	Mar 23, 2023	Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jan 15, 2014	The p.K893N variant (also known as c.2679G>Tor 2798G>T), located in coding exon 9 of the BRCA1 gene, results from a G to T substitution at nucleotide position 2679. The lysine at codon 893 is replaced by asparagine, an amino acid with a few similar properties. This 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. This amino acid position is poorly conserved in available vertebrate species.In addition, this alteration is predicted to be possibly damaging by PolyPhen but tolerated by SIFT in silico analyses. Since supporting evidence is limited at this time, the clinical significance of p.K893N remains unclear. -

BRCA1-related cancer predisposition Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Mar 05, 2024

This missense variant replaces lysine with asparagine at codon 893 of the BRCA1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 09, 2023

This variant has not been reported in the literature in individuals affected with BRCA1-related conditions. 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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt BRCA1 protein function. ClinVar contains an entry for this variant (Variation ID: 141468). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces lysine, which is basic and polar, with asparagine, which is neutral and polar, at codon 893 of the BRCA1 protein (p.Lys893Asn). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Benign	-0.017	T
BayesDel_noAF	Benign	-0.26
CADD	Benign	15
DANN	Benign	0.97
DEOGEN2	Benign	0.27	T;.;.;.
Eigen	Benign	-0.91
Eigen_PC	Benign	-1.0
FATHMM_MKL	Benign	0.054	N
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Uncertain	0.11	D
MetaRNN	Benign	0.17	T;T;T;T
MetaSVM	Benign	-0.54	T
MutationAssessor	Benign	1.7	L;L;.;.
PrimateAI	Benign	0.23	T
PROVEAN	Benign	-1.9	N;N;N;N
REVEL	Uncertain	0.29
Sift	Uncertain	0.0030	D;D;D;D
Sift4G	Benign	0.39	T;T;T;D
Polyphen		0.74	P;.;.;B
Vest4		0.31
MutPred		0.31		Loss of methylation at K893 (P = 0.0098);Loss of methylation at K893 (P = 0.0098);.;Loss of methylation at K893 (P = 0.0098);
MVP		0.59
MPC		0.16
ClinPred		0.061	T
GERP RS		-1.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.084
gMVP		0.060

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: rs587781771; hg19: chr17-41244869; COSMIC: COSV58786902; COSMIC: COSV58786902;