17-43047703-C-T

Variant names:

• chr17-43047703-C-T
• rs876659510
• NM_007294.4:c.5407G>A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_007294.4(BRCA1):​c.5407G>A​(p.Gly1803Ser) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,856 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BRCA1 NM_007294.4 missense, splice_region
• Scores: Splicing: ADA: 0.7579
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4 O:1
• Conservation: PhyloP100: 1.78

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 5 ACMG points.

• PM1: In a domain BRCT 2 (size 99) in uniprot entity BRCA1_HUMAN there are 69 pathogenic changes around while only 15 benign (82%) in NM_007294.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.745

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.5407G>A	p.Gly1803Ser	missense_variant, splice_region_variant	Exon 22 of 23	ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.5407G>A	p.Gly1803Ser	missense_variant, splice_region_variant	Exon 22 of 23	1	NM_007294.4	ENSP00000350283.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461856 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727228

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

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Jul 08, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G1803S variant (also known as c.5407G>A) is located in coding exon 21 of the BRCA1 gene. The glycine at codon 1803 is replaced by serine, an amino acid with similar properties. This change occurs in the first base pair of coding exon 21. One functional study found that this nucleotide substitution is functional in a high-throughput, genome editing, haploid cell survival assay (Findlay GM et al. Nature, 2018 10;562:217-222). However, another study reported this variant had impaired homologous recombination activity (Guo Q et al. J Hum Genet. 2023 Dec;68(12):849-857). A close match alteration, BRCA2 c.5408G>C (p.G1803A) is also functional in the cell survival assay, protein folding, binding activity and binding specificity, but has compromised transactivation activity (Lee MS et al. Cancer Res. 2010 Jun;70:4880-90; Findlay GM et al. Nature, 2018 10;562:217-222; Fernandes VC et al. J. Biol. Chem.. 2019 04;294:5980-5992). This close match has also been described as having a splice defect (Wappenschmidt B et al. PLoS ONE. 2012 Dec;7:e50800; Ahlborn LB et al. Breast Cancer Res. Treat. 2015 Apr;150:289-98; Ambry internal data). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Aug 03, 2020

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces glycine with serine at codon 1803 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 not been reported in individuals affected with hereditary cancer in the literature. 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. -

not specified Uncertain:1

Jun 01, 2018

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: BRCA1 c.5407G>A (p.Gly1803Ser) results in a non-conservative amino acid change located in the second C-terminal domain (BRCT domain (IPR001357)) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant alters the first nucleotide of exon 22 and several computational tools predict a significant impact on normal splicing: four predict the variant weakens a 3 acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 121582 control chromosomes (in ExAC). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.5407G>A has been reported in the literature in individuals affected with Hereditary Breast and Ovarian Cancer (Wagner 1999). This report does not provide unequivocal conclusions about association of the variant with Hereditary Breast and Ovarian Cancer. At least one publication reports experimental evidence evaluating an impact on protein function, however, it does not allow convincing conclusions about the variant effect (Findlay 2018). One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, and classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Hereditary breast ovarian cancer syndrome Uncertain:1

May 13, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 1803 of the BRCA1 protein (p.Gly1803Ser). 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: 232037). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -

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

-

Brotman Baty Institute, University of Washington

Significance: not provided

Review Status: no classification provided

Collection Method: in vitro

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.081
BayesDel_addAF	Uncertain	0.080	D
BayesDel_noAF	Benign	-0.12
CADD	Benign	19
DANN	Uncertain	0.99
Eigen	Benign	-0.10
Eigen_PC	Benign	-0.11
FATHMM_MKL	Benign	0.55	D
LIST_S2	Benign	0.34	T
M_CAP	Pathogenic	0.71	D
MetaRNN	Pathogenic	0.74	D
MetaSVM	Uncertain	0.094	D
PROVEAN	Benign	0.11	N
REVEL	Uncertain	0.34
Sift	Uncertain	0.0040	D
Sift4G	Pathogenic	0.0	D
Vest4		0.62
MutPred		0.20		Loss of relative solvent accessibility (P = 0.107);
MVP		0.63
ClinPred		0.94	D
GERP RS		4.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.76
dbscSNV1_RF	Pathogenic	0.79
SpliceAI score (max)		0.090		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: rs876659510; hg19: chr17-41199720;