17-43094704-G-T

Position:

• chr17-43094704-G-T

Variant summary

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

The NM_007294.4(BRCA1):​c.827C>A​(p.Thr276Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000658 in 151,990 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. T276R) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: BRCA1 NM_007294.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:1
• Conservation: PhyloP100: 1.05

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 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
BRCA1	NM_007294.4	c.827C>A	p.Thr276Lys	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.827C>A	p.Thr276Lys	missense_variant	10/23	1	NM_007294.4	ENSP00000350283.3

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151990 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 34

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151990 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74210

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Mar 06, 2024	The p.T276K variant (also known as c.827C>A), located in coding exon 9 of the BRCA1 gene, results from a C to A substitution at nucleotide position 827. The threonine at codon 276 is replaced by lysine, an amino acid with similar properties. This amino acid position is conserved. 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). -

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

Uncertain significance, no assertion criteria provided

clinical testing

Sharing Clinical Reports Project (SCRP)

Feb 07, 2012

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Jul 31, 2018

- -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 30, 2023

This sequence change replaces threonine, which is neutral and polar, with lysine, which is basic and polar, at codon 276 of the BRCA1 protein (p.Thr276Lys). 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: 252891). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Benign	21
DANN	Benign	0.96
DEOGEN2	Uncertain	0.53	D;.;.;.;T;T;.;T
Eigen	Benign	0.10
Eigen_PC	Benign	0.12
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Benign	0.78	T;T;T;T;T;T;T;T
M_CAP	Uncertain	0.26	D
MetaRNN	Uncertain	0.52	D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.54	D
MutationAssessor	Pathogenic	3.2	M;M;.;.;.;.;.;.
PrimateAI	Benign	0.42	T
PROVEAN	Uncertain	-4.0	D;D;D;D;.;D;D;D
REVEL	Uncertain	0.61
Sift	Uncertain	0.017	D;D;D;D;.;D;D;D
Sift4G	Benign	0.14	T;T;T;D;.;D;.;D
Polyphen		0.95	P;.;.;B;.;.;.;.
Vest4		0.47
MutPred		0.30		Loss of catalytic residue at T276 (P = 6e-04);Loss of catalytic residue at T276 (P = 6e-04);.;Loss of catalytic residue at T276 (P = 6e-04);.;Loss of catalytic residue at T276 (P = 6e-04);.;Loss of catalytic residue at T276 (P = 6e-04);
MVP		0.90
MPC		0.20
ClinPred		0.89	D
GERP RS		4.0
Varity_R		0.19
gMVP		0.34

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: rs80357436; hg19: chr17-41246721; COSMIC: COSV58785845; COSMIC: COSV58785845;