17-43094642-T-G

Position:

• chr17-43094642-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 10P and 1B. PVS1 PM2 BP6

The ENST00000497488.2(BRCA1):​c.1A>C​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,874 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).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BRCA1 ENST00000497488.2 start_lost
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6 B:3
• Conservation: PhyloP100: 1.01

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 Likely_pathogenic. Variant got 9 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PM2: Very rare variant in population databases, with high coverage
• BP6: Variant 17-43094642-T-G is Benign according to our data. Variant chr17-43094642-T-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 55741.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=5, Likely_benign=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA1	NM_007294.4	c.889A>C	p.Met297Leu	missense_variant	10/23	ENST00000357654.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA1	ENST00000357654.9	c.889A>C	p.Met297Leu	missense_variant	10/23	1	NM_007294.4	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461874 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 727236

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

Bravo AF: 0.00000756

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6 Benign:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

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

Likely benign, no assertion criteria provided	clinical testing	Department of Medical and Surgical Sciences, University of Bologna	Sep 01, 2023	PM2(Supporting)+BP1(Strong) according to ACMG/AMP classification guidelines specified for BRCA1 & BRCA2 (Classification Criteria V1.0.0 2023-09-08 - https://cspec.genome.network/cspec/ui/svi/affiliation/50087) (PMID: 38160042) -
Uncertain significance, no assertion criteria provided	clinical testing	Breast Cancer Information Core (BIC) (BRCA1)	May 29, 2002	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	May 03, 2018	- -

Hereditary cancer-predisposing syndrome Uncertain:2 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jul 12, 2023	The p.M297L variant (also known as c.889A>C), located in coding exon 9 of the BRCA1 gene, results from an A to C substitution at nucleotide position 889. The methionine at codon 297 is replaced by leucine, an amino acid with highly similar properties. This alteration was reported in trans with a BRCA1 pathogenic mutation based on haplotype analysis in a patient with breast and/or ovarian cancer who underwent clinical genetic testing, and was classified as a variant of unknown significance (Judkins T et al. Cancer Res. 2005 Nov;65(21):10096-103). In a study of 1854 high-risk breast/ovarian cancer families in Italy, this alteration was detected in one family (Azzollini J et al. Eur. J. Intern. Med., 2016 Jul;32:65-71). This alteration was also observed in 1 of 1045 Italian patients with breast and/or ovarian cancer fulfilling established criteria for HBOC genetic testing (Zuntini R et al. Front Genet, 2018 Sep;9:378). 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jun 07, 2022	This missense variant replaces methionine with leucine at codon 297 of the BRCA1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in at least one individual affected with breast cancer and one suspected hereditary breast and ovarian cancer family (PMID: 27062684, 30254663, 32380732, 34178674). 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. -
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). -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jul 26, 2022

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Also known as 1008A>C; Observed in individuals with breast and/or ovarian cancer (Azzollini et al., 2016; Zuntini et al., 2018; Fanale et al., 2021); This variant is associated with the following publications: (PMID: 31131967, 27062684, 16267036, 15235020, 34178674, 30254663, 20215511, 15343273, 9788437, 9926942, 9582019) -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 23, 2023

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. ClinVar contains an entry for this variant (Variation ID: 55741). This missense change has been observed in individual(s) with clinical features of BRCA1-related conditions (PMID: 15235020, 27062684, 30254663, 34178674). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces methionine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 297 of the BRCA1 protein (p.Met297Leu). -

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Cancer Genetics and Genomics Laboratory, British Columbia Cancer Agency

Apr 18, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.16	D
BayesDel_noAF	Uncertain	-0.010
CADD	Benign	13
DANN	Benign	0.79
DEOGEN2	Benign	0.32	T;.;.;.;T;T;.;.;T
Eigen	Benign	-0.51
Eigen_PC	Benign	-0.44
FATHMM_MKL	Uncertain	0.79	D
LIST_S2	Benign	0.81	T;T;T;T;T;T;T;D;T
M_CAP	Uncertain	0.091	D
MetaRNN	Benign	0.23	T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.28	T
MutationAssessor	Uncertain	2.3	M;M;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;N;N;N;N;N
PrimateAI	Benign	0.45	T
PROVEAN	Benign	-2.4	N;N;N;N;.;N;N;N;N
REVEL	Uncertain	0.50
Sift	Benign	0.15	T;T;T;T;.;T;T;T;T
Sift4G	Benign	0.28	T;T;T;T;.;T;.;T;T
Polyphen		0.0030	B;.;.;B;.;.;.;.;.
Vest4		0.33
MutPred		0.38		Gain of helix (P = 0.0325);Gain of helix (P = 0.0325);.;Gain of helix (P = 0.0325);.;Gain of helix (P = 0.0325);.;.;Gain of helix (P = 0.0325);
MVP		0.67
MPC		0.077
ClinPred		0.39	T
GERP RS		-0.16
Varity_R		0.15
gMVP		0.17

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: rs80357196; hg19: chr17-41246659;