chr17-43049192-G-C

Variant names:

• chr17-43049192-G-C
• rs397509267
• NM_007294.4:c.5335C>G

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_007294.4(BRCA1):​c.5335C>G​(p.Gln1779Glu) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,554 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. 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. Q1779H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BRCA1 NM_007294.4 missense, splice_region
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:1
• Conservation: PhyloP100: 1.86
• Publications: 11 publications found

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 Gene-Disease associations (from GenCC):

• breast-ovarian cancer, familial, susceptibility to, 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, ClinGen, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• Fanconi anemia, complementation group S

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
• pancreatic cancer, susceptibility to, 4

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• hereditary breast ovarian cancer syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Fanconi anemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM1: In a hotspot region, there are 15 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 16 benign, 80 uncertain in NM_007294.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.34419328).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.5335C>G	p.Gln1779Glu	missense_variant, splice_region_variant	Exon 21 of 23	ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.5335C>G	p.Gln1779Glu	missense_variant, splice_region_variant	Exon 21 of 23	1	NM_007294.4	ENSP00000350283.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251414 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461554 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727116

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111714

Other (OTH) AF: 0.0000166 AC: 1 AN: 60382

GnomAD4 genome Cov.: 31

Alfa AF: 0.0000318 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Dec 05, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces glutamine with glutamic acid at codon 1779 of the BRCA1 protein. Computational prediction suggests that this variant may not impact protein structure and function. This variant has been reported to be functional in a haploid cell proliferation assay (PMID: 30209399). This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 1/251414 chromosomes 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.

Oct 27, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Q1779E variant (also known as c.5335C>G), located in coding exon 20 of the BRCA1 gene, results from a C to G substitution at nucleotide position 5335. The glutamine at codon 1779 is replaced by glutamic acid, an amino acid with highly similar properties. 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.

BRCA1-related cancer predisposition Uncertain:1

May 30, 2024

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces glutamine with glutamic acid at codon 1779 of the BRCA1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). Splice site prediction tools suggest that this variant may not impact RNA splicing. This variant has been reported to be functional in a haploid cell proliferation assay (PMID: 30209399). This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 1/251414 chromosomes 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 provided Uncertain:1

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The BRCA1 p.Gln1779Glu variant was not identified in the literature nor was it identified in the dbSNP, ClinVar, LOVD 3.0, or UMD-LSDB, databases. The variant was identified in control databases in 1 of 246196 chromosomes at a frequency of 0.000004 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the European in 1 of 111660 chromosomes (freq: 0.000009), while the variant was not observed in the African, Other, Latino, Ashkenazi Jewish, East Asian, Finnish, and South Asian populations. The p.Gln1779 residue is not conserved in mammals and four out of five computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood of impact to the protein; however, this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence and 1 of 4 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) predict a greater than 10% difference in splicing, however, this information is not predictive enough to assume pathogenicity. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance.

Hereditary breast ovarian cancer syndrome Uncertain:1

Aug 06, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamine, which is neutral and polar, with glutamic acid, which is acidic and polar, at codon 1779 of the BRCA1 protein (p.Gln1779Glu). This variant is present in population databases (no rsID available, gnomAD 0.0009%). 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: 825658). An algorithm developed to predict the effect of missense changes on protein structure and function outputs the following: PolyPhen-2: "Possibly Damaging". The glutamic acid amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Experimental studies have shown that this missense change does not substantially affect BRCA1 function (PMID: 30209399). 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 Benign:1

Apr 12, 2024

Lupski Lab, Baylor-Hopkins CMG, Baylor College of Medicine

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: curation

Each variant was annotated with functional scores from MAVE data which was translated into functional evidence codes. All other evidence codes and combining criteria were adhered to as closely as possible based on the ClinGen VCEP (Variant Curation Expert Panel) gene-specific recommendations. See Supplemental Figure 34 of final paper (Supp Fig. 28 in preprint: doi:10.1101/2024.04.11.24305690) for a table to see which lines of evidence we did not have data for. The ClinGen VCEPs are highly regarded as the gold-standard for gene-specific variant curation and are developed after extensive evaluation of the evidence by clinical and scientific experts for the particular gene to classify genomic variants on a spectrum from pathogenic to benign using the 2015 ACMG/AMP Variant Interpretation Guidelines as a backbone (PMID: 25741868). Reclassification of these VUS variants from gnomAD or All of Us focused only on variants originally prescribed as VUS in ClinVar. To ensure reproducibility, transparency, and increased throughput, all the procedures for annotating variants and assigning evidence codes were codified using Python. All code has been made freely available and is linked in the Code Availability section and all reclassified variants with evidence codes used can be found in Tables S18-19 (preprint: doi:10.1101/2024.04.11.24305690). For the MAVE data, the clinical curation and clinical strength assignment as per the ClinGen recommendations in Brnich et al. (2020) (PMID: 31892348) for or against pathogenicity or benignity of each of these MAVE datasets utilized in this study were previously published in Fayer et al. (2021) (PMID: 34793697).In brief, for BRCA1 variants, if a variant was categorized as FUNC (functional), it was assigned BS3 evidence and no PS3 evidence, whereas if it was categorized as LOF (loss of function), the variant was assigned PS3 evidence and no BS3 evidence. Variants categorized as INT (intermediate) were left unannotated. For the BRCA1 combining criteria, greater than or equal to 1 criteria of strong benign evidence was enough to reclassify the VUS as Likely Benign. This variant GRCh37:17:41201209:G>C was assigned evidence codes ['BS3', 'BP4'] and an overall classification of Likely Benign

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.094
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.0
CADD	Benign	18
DANN	Benign	0.91
DEOGEN2	Benign	0.0	.;T;.;T;T;T;.;.
Eigen	Benign	-0.031
Eigen_PC	Benign	0.037
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Uncertain	0.91	D;D;D;T;D;D;D;D
M_CAP	Uncertain	0.18	D
MetaRNN	Benign	0.34	T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.54	T
MutationAssessor	Benign	0.0	.;L;.;.;.;.;.;.
PhyloP100		1.9
PrimateAI	Benign	0.32	T
PROVEAN	Benign	-0.55	N;N;.;.;.;.;N;N
REVEL	Uncertain	0.30
Sift	Benign	0.23	T;T;.;.;.;.;T;T
Sift4G	Benign	0.85	T;T;T;D;T;T;T;T
Vest4		0.38
ClinPred		0.39	T
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.15
gMVP		0.38

Splicing

Name	Calibrated prediction	Score	Prediction
Splicevardb		1.0
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

Other links and lift over

dbSNP: rs397509267; hg19: chr17-41201209;