rs80358054

chr17-43074523-T-Achr17-43074523-T-Cchr17-43074523-T-G

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PVS1 PM2 PP3_Strong PP5_Moderate

The NM_007294.4(BRCA1):c.4485-2A>T variant causes a splice acceptor change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: BRCA1 NM_007294.4 splice_acceptor
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 3.42

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 Pathogenic. Variant got 16 ACMG points.

• PVS1: Splicing variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 17-43074523-T-A is Pathogenic according to our data. Variant chr17-43074523-T-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 433715.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA1	NM_007294.4	c.4485-2A>T		splice_acceptor_variant		ENST00000357654.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA1	ENST00000357654.9	c.4485-2A>T		splice_acceptor_variant		1	NM_007294.4	P4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Malignant tumor of breast Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

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The c.4485-2A>T variant has not been previously reported in the literature. It is predicted to cause abnormal splicing because the nucleotide substitution occurs in the -2 position of the 5' splice site of the splice consensus sequence. Furthermore, in-silico or computational prediction software (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) predicts a greater than 10% difference in splicing in 5 of 5 different programs increasing the likelihood this variant causes abnormal splicing. In addition, another variant at this same position, different nucleotide change (c.4485-2A>G), has been previously reported in the HGMD and 7x in the BIC database as a clinically significant variant. In summary, based on the above information, this variant meets our laboratory's criteria to be classified as pathogenic. -

Hereditary breast ovarian cancer syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Nov 08, 2017

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in BRCA1 are known to be pathogenic (PMID: 20104584). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with BRCA1-related disease. ClinVar contains an entry for this variant (Variation ID: 433715). This variant is not present in population databases (ExAC no frequency). This sequence change affects an acceptor splice site in intron 13 of the BRCA1 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.11	T
BayesDel_noAF	Benign	-0.39
Cadd	Pathogenic	34
Dann	Benign	0.88
Eigen	Pathogenic	0.74
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Uncertain	0.80	D
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D
GERP RS		5.4

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		0.97		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.56		Position offset: -31
DS_AL_spliceai		0.97		Position offset: -2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs80358054; hg19: chr17-41226540;