17-43093373-C-T

Position:

• chr17-43093373-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4 BP6

The NM_007294.4(BRCA1):​c.2158G>A​(p.Glu720Lys) 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 1,461,722 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E720G) has been classified as Likely benign.

• 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:4 B:1
• Conservation: PhyloP100: 0.574

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]

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=0.28328043).
• BP6: Variant 17-43093373-C-T is Benign according to our data. Variant chr17-43093373-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 54479.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=2, Likely_benign=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA1	NM_007294.4	c.2158G>A	p.Glu720Lys	missense_variant	10/23	ENST00000357654.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA1	ENST00000357654.9	c.2158G>A	p.Glu720Lys	missense_variant	10/23	1	NM_007294.4	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000797 AC: 2 AN: 250954 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135688

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461722 Hom.: 0 Cov.: 41 AF XY: 0.00000138 AC XY: 1 AN XY: 727158

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

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

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

Uncertain significance, no assertion criteria provided	clinical testing	Sharing Clinical Reports Project (SCRP)	Nov 23, 2010	- -
Uncertain significance, no assertion criteria provided	clinical testing	Breast Cancer Information Core (BIC) (BRCA1)	Oct 19, 2011	- -

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jan 11, 2024	The p.E720K variant (also known as c.2158G>A), located in coding exon 9 of the BRCA1 gene, results from a G to A substitution at nucleotide position 2158. The glutamic acid at codon 720 is replaced by lysine, an amino acid with similar properties. In a study of whole-exome sequencing in patients with features of Cowden syndrome (CS) or Bannayan-Riley-Ruvalcaba syndrome (BRRS) and negative PTEN testing, this alteration was identified in 0/87 patients with CS or BRRS and 1/3476 patients from The Cancer Genome Atlas (TCGA) (Yehia L et al. PLoS Genet, 2018 04;14:e1007352). This amino acid position is not 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. -
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). -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 22, 2023

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 720 of the BRCA1 protein (p.Glu720Lys). This variant is present in population databases (rs80356875, gnomAD 0.002%). This missense change has been observed in individual(s) with breast cancer (PMID: 29625052). ClinVar contains an entry for this variant (Variation ID: 54479). 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. Experimental studies have shown that this missense change does not substantially affect BRCA1 function (PMID: 26689913). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Uncertain	0.0
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.63	D;.;.;.;T
Eigen	Benign	-0.16
Eigen_PC	Benign	-0.28
FATHMM_MKL	Benign	0.12	N
LIST_S2	Uncertain	0.88	D;D;D;D;D
M_CAP	Uncertain	0.28	D
MetaRNN	Benign	0.28	T;T;T;T;T
MetaSVM	Uncertain	-0.26	T
MutationAssessor	Uncertain	2.7	M;M;.;.;.
MutationTaster	Benign	1.0	N;N;N;N;N;N;N;N;N;N;N;N;N;N
PrimateAI	Benign	0.27	T
PROVEAN	Uncertain	-3.2	D;D;D;D;.
REVEL	Uncertain	0.55
Sift	Benign	0.054	T;D;T;T;.
Sift4G	Benign	0.24	T;T;T;T;.
Polyphen		0.37	B;.;.;D;.
Vest4		0.38
MutPred		0.35		Gain of ubiquitination at E720 (P = 6e-04);Gain of ubiquitination at E720 (P = 6e-04);.;Gain of ubiquitination at E720 (P = 6e-04);.;
MVP		0.72
MPC		0.48
ClinPred		0.65	D
GERP RS		3.5
Varity_R		0.093
gMVP		0.13

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: rs80356875; hg19: chr17-41245390;