chr17-43099793-A-T

Position:

• chr17-43099793-A-T

Variant summary

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

The NM_007294.4(BRCA1):​c.529T>A​(p.Ser177Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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. S177F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: BRCA1 NM_007294.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 1.52

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA1	NM_007294.4	c.529T>A	p.Ser177Thr	missense_variant	7/23	ENST00000357654.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA1	ENST00000357654.9	c.529T>A	p.Ser177Thr	missense_variant	7/23	1	NM_007294.4	P4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Apr 22, 2024

Variant summary: BRCA1 c.529T>A (p.Ser177Thr) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant was absent in 251454 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.529T>A has been reported in the literature in an individual affected with breast cancer without strong evidence for causality (example: Keshavarzi_2013). These report(s) do not provide unequivocal conclusions about association of the variant with Hereditary Breast And Ovarian Cancer Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 21918854). ClinVar contains an entry for this variant (Variation ID: 481474). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 27, 2019

The p.S177T variant (also known as c.529T>A), located in coding exon 6 of the BRCA1 gene, results from a T to A substitution at nucleotide position 529. The serine at codon 177 is replaced by threonine, an amino acid with similar properties. This alteration was detected in a woman with breast cancer diagnosed before the age of 35 years in a study of 85 high-risk Iranian breast cancer families; however, the study authors classified this alteration as a polymorphism (Keshavarzi F et al. Fam. Cancer, 2012 Mar;11:57-67). This amino acid position is 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. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 27, 2022

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: 481474). This missense change has been observed in individual(s) with breast cancer (PMID: 21918854). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces serine, which is neutral and polar, with threonine, which is neutral and polar, at codon 177 of the BRCA1 protein (p.Ser177Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Benign	21
DANN	Uncertain	0.98
DEOGEN2	Benign	0.22	.;T;.;.;.;.;.;T;.;T;.;T;T;.;T;T
Eigen	Uncertain	0.21
Eigen_PC	Benign	0.15
FATHMM_MKL	Benign	0.65	D
LIST_S2	Uncertain	0.90	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.78	D
MetaRNN	Uncertain	0.49	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Uncertain	2.5	M;M;M;M;.;M;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;N;N;N;N;N;N;N;N;N;N
PrimateAI	Benign	0.42	T
PROVEAN	Benign	-1.1	N;N;N;N;N;N;N;N;N;N;N;.;N;N;N;N
REVEL	Uncertain	0.58
Sift	Benign	0.038	D;D;D;D;D;D;D;D;D;D;D;.;D;D;D;D
Sift4G	Benign	0.062	T;D;D;T;D;T;.;.;D;.;D;.;D;.;D;.
Polyphen		0.96, 0.98, 0.89	.;P;.;.;.;D;.;D;.;.;P;.;.;.;.;.
Vest4		0.47
MutPred		0.27		Loss of disorder (P = 0.0876);Loss of disorder (P = 0.0876);Loss of disorder (P = 0.0876);Loss of disorder (P = 0.0876);.;Loss of disorder (P = 0.0876);.;.;.;.;Loss of disorder (P = 0.0876);Loss of disorder (P = 0.0876);Loss of disorder (P = 0.0876);.;Loss of disorder (P = 0.0876);.;
MVP		0.96
MPC		0.28
ClinPred		0.76	D
GERP RS		2.7
Varity_R		0.082
gMVP		0.21

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: rs1555594827; hg19: chr17-41251810;