rs273900733

Positions:

• chr17-43099882-TA-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The ENST00000357654.9(BRCA1):​c.442-3del variant causes a splice region, splice polypyrimidine tract, intron change. The variant allele was found at a frequency of 0.00000138 in 1,453,288 control chromosomes in the GnomAD database, with no homozygous occurrence. 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).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: BRCA1 ENST00000357654.9 splice_region, splice_polypyrimidine_tract, intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:1
• Conservation: PhyloP100: 3.92

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.442-3del		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.442-3del		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_007294.4	ENSP00000350283	P4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000138 AC: 2 AN: 1453288 Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1 AN XY: 723542

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: 0.00000181

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Apr 06, 2019	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Dec 02, 2021	The c.442-3delT intronic variant, located in intron 5 of the BRCA1 gene, results from a deletion of one nucleotide within intron 5 of the BRCA1 gene. This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will not have any significant effect on splicing. This splice acceptor site has a naturally occurring isoform (Δ8p in the literature) that uses an alternative acceptor and results in the deletion of a single amino acid from the beginning of coding exon 6 (Ambry internal data; Colombo M et al. Hum Mol Genet., 2014 Jul;23:3666-80). The functional and clinical significance of this single amino acid loss is unknown. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

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

Uncertain significance, no assertion criteria provided

clinical testing

Breast Cancer Information Core (BIC) (BRCA1)

Nov 14, 1997

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Nov 14, 2023

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports a deleterious effect on splicing; Has not been previously published as pathogenic or benign to our knowledge; Also known as 561-3del -

Hereditary breast ovarian cancer syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 06, 2023

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
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: rs273900733; hg19: chr17-41251899;