rs587781833

Positions:

• chr17-43094765-T-A
• chr17-43094765-T-C
• chr17-43094765-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_007294.4(BRCA1):​c.766A>T​(p.Arg256Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,300 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). Synonymous variant affecting the same amino acid position (i.e. RH256N?) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-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: 1.22

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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.41586947).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.766A>T	p.Arg256Trp	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.766A>T	p.Arg256Trp	missense_variant	10/23	1	NM_007294.4	ENSP00000350283.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459300 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 725766

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary breast ovarian cancer syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Institute for Biomarker Research, Medical Diagnostic Laboratories, L.L.C.	May 14, 2024	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 12, 2022	This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 256 of the BRCA1 protein (p.Arg256Trp). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with BRCA1-related conditions. ClinVar contains an entry for this variant (Variation ID: 141549). 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. 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. -

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Dec 17, 2021	The p.R256W variant (also known as c.766A>T), located in coding exon 9 of the BRCA1 gene, results from an A to T substitution at nucleotide position 766. The arginine at codon 256 is replaced by tryptophan, an amino acid with dissimilar properties. Based on protein sequence alignment, this amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. 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). -

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

Uncertain significance, no assertion criteria provided

clinical testing

BRCAlab, Lund University

Mar 02, 2020

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
CADD	Uncertain	24
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.24	T;.;.;.;.;.;T;.;T;.;T;T;.;T
Eigen	Uncertain	0.22
Eigen_PC	Benign	0.21
FATHMM_MKL	Benign	0.47	N
LIST_S2	Pathogenic	0.98	D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.74	D
MetaRNN	Benign	0.42	T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Pathogenic	0.80	D
MutationAssessor	Benign	1.7	L;L;L;.;L;.;.;.;.;.;.;.;.;.
PrimateAI	Benign	0.22	T
PROVEAN	Benign	-1.2	N;N;N;N;N;N;N;N;D;N;.;N;N;N
REVEL	Uncertain	0.58
Sift	Uncertain	0.0010	D;D;D;D;D;D;D;D;D;D;.;D;D;D
Sift4G	Uncertain	0.019	D;D;D;D;D;.;.;D;.;D;.;D;.;D
Polyphen		0.99	D;.;.;.;P;.;D;.;.;D;.;.;.;.
Vest4		0.38
MutPred		0.30		Gain of helix (P = 0.0496);Gain of helix (P = 0.0496);Gain of helix (P = 0.0496);.;Gain of helix (P = 0.0496);.;.;.;.;Gain of helix (P = 0.0496);.;Gain of helix (P = 0.0496);.;Gain of helix (P = 0.0496);
MVP		0.92
MPC		0.41
ClinPred		0.83	D
GERP RS		3.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.070
gMVP		0.24

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: rs587781833; hg19: chr17-41246782;