chr17-43057074-G-C

Position:

• chr17-43057074-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PM5 PP3

The NM_007294.4(BRCA1):​c.5255C>G​(p.Ala1752Gly) variant causes a missense change. The variant allele was found at a frequency of 0.00000342 in 1,461,792 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. A1752S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: BRCA1 NM_007294.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3 O:1
• Conservation: PhyloP100: 5.96

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 7 ACMG points.

• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 7 benign, 17 uncertain in NM_007294.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-43057075-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 55483.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.807

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA1	NM_007294.4	c.5255C>G	p.Ala1752Gly	missense_variant	19/23	ENST00000357654.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA1	ENST00000357654.9	c.5255C>G	p.Ala1752Gly	missense_variant	19/23	1	NM_007294.4	P4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461792 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727208

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000126

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Sep 26, 2023	This missense variant substitutes alanine with glycine at codon 1752 in 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). A functional study has reported that this variant does not impact BRCA1 function in a haploid cell proliferation assay (PMID: 30209399). This variant has been detected in one individual affected with breast cancer and confirmed to be absent in a breast cancer affected sister (PMID: 23842040). This variant has been reported in a breast cancer case-control study in 1/7051 female breast cancer cases and 4/11241 unaffected female controls (PMID: 30287823), and in a pancreatic cancer case-control study in 0/1005 cases and 8/23705 unaffected individuals (PMID: 32980694). This variant also has been reported in a prostate cancer case-control study in 3/7636 cases and 4/12366 unaffected individuals (PMID: 31214711). 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Apr 17, 2019	The p.A1752G variant (also known as c.5255C>G), located in coding exon 18 of the BRCA1 gene, results from a C to G substitution at nucleotide position 5255. The alanine at codon 1752 is replaced by glycine, an amino acid with similar properties. This alteration was reported in a Japanese female who was diagnosed with breast cancer at age 46 and had a family history of breast cancer in her sister and her father. However, her affected sister was not found to have this variant, and her father was not available for testing (Kawaku S et al. J. Hum. Genet. 2013 Sep; 58(9):618-21.) This alteration has also been reported with a carrier frequency of 1 in 7051 unselected breast cancer patients and 4 in 11241 female controls of Japanese ancestry (Momozawa Y et al. Nat Commun, 2018 10;9:4083). One functional study found that this nucleotide substitution is tolerated in a high throughput genome editing haploid cell survival assay (Findlay GM et al. Nature, 2018 10;562:217-222). This amino acid position is 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. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 09, 2023

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. This variant disrupts the p.Ala1752 amino acid residue in BRCA1. Other variant(s) that disrupt this residue have been determined to be pathogenic (Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change does not substantially affect BRCA1 function (PMID: 23842040, 30209399). Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (PMID: 30209399) indicates that this missense variant is not expected to disrupt BRCA1 function. ClinVar contains an entry for this variant (Variation ID: 482908). This missense change has been observed in individual(s) with breast cancer (PMID: 23842040, 30287823). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 1752 of the BRCA1 protein (p.Ala1752Gly). -

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

not provided, no classification provided

in vitro

Brotman Baty Institute, University of Washington

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.11	.;T;.;.;T;T;.;.
Eigen	Uncertain	0.41
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.96	D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.31	D
MetaRNN	Pathogenic	0.81	D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.66	D
MutationAssessor	Benign	1.9	.;L;.;.;.;.;.;.
MutationTaster	Benign	0.88	D;D;D;D;D;D;D;D;D;D;D;D;N;N
PrimateAI	Benign	0.36	T
PROVEAN	Uncertain	-2.7	D;N;.;D;.;.;N;D
REVEL	Uncertain	0.64
Sift	Benign	0.061	T;D;.;T;.;.;D;T
Sift4G	Uncertain	0.015	D;D;D;D;D;D;D;D
Polyphen		0.38, 0.74	.;B;.;.;.;P;.;.
Vest4		0.72
MVP		0.91
MPC		0.083
ClinPred		0.90	D
GERP RS		5.1
Varity_R		0.42
gMVP		0.57

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: rs80357028; hg19: chr17-41209091;