17-43074331-C-T
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM2PM5PP3_StrongPP5_Very_Strong
The NM_007294.4(BRCA1):c.4675G>A(p.Glu1559Lys) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,716 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E1559V) has been classified as Uncertain significance.
Frequency
Consequence
NM_007294.4 missense, splice_region
Scores
Clinical Significance
Conservation
Publications
- breast-ovarian cancer, familial, susceptibility to, 1Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, ClinGen, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
- Fanconi anemia, complementation group SInheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
- pancreatic cancer, susceptibility to, 4Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
- hereditary breast ovarian cancer syndromeInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Fanconi anemiaInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152112Hom.: 0 Cov.: 32 show subpopulations
GnomAD4 exome AF: 6.84e-7 AC: 1AN: 1461604Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1AN XY: 727118 show subpopulations ⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152112Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74294 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Pathogenic:7
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BRCA1: PVS1, PM2, PS4:Moderate -
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RNA studies demonstrate a damaging effect: aberrant splicing leading to the loss of the last 11 nucleotides, resulting in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease (PMID: 23239986, 31143303); Multifactorial likelihood analysis suggests this variant is pathogenic (PMID: 31131967); Not observed at significant frequency in large population cohorts (gnomAD); Truncating variants in this gene are considered pathogenic by a well-established clinical consortium and/or database; Also known as 4794G>A; This variant is associated with the following publications: (PMID: 31825140, 29752822, 29446198, 31131967, 30441849, 33468216, 29797126, 36922883, 31294896, 30765603, 32546644, 32341426, 9974970, 11301010, 10220405, 37937776, 28781887, 33087888, 24333842, 34981296, 36367610, 17761984, 23239986, 31143303, 25066507, 24797986) -
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The BRCA1 c.4675G>A (p.Glu1559Lys) variant has been reported in the published literature in in multiple individuals and families with breast and/or ovarian cancer (PMIDs: 33471991 (2021), 32341426 (2020), 31825140 (2019), 30441849 (2018), 29797126 (2018), 29752822 (2018), 29446198 (2018), 25066507 (2014), 24797986 (2014), 23239986 (2012)). Functional analysis indicates that this variant interferes with normal RNA splicing (PMIDs: 31143303 (2019) and 23239986 (2012)). The frequency of this variant in the general population, 0.000032 (1/31378 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is consistent with pathogenicity. Analysis of this variant using software algorithms for the prediction of the effect of nucleotide changes on splicing yielded predictions that this variant may affect proper BRCA1 mRNA splicing. Based on the available information, this variant is classified as pathogenic. -
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Breast-ovarian cancer, familial, susceptibility to, 1 Pathogenic:6
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IARC class based on posterior probability from multifactorial likelihood analysis, thresholds for class as per Plon et al. 2008 (PMID: 18951446). Class 5 based on posterior probability = 0.99607 -
Criteria applied: PS3,PS4,PM2_SUP, PP3 -
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Hereditary breast ovarian cancer syndrome Pathogenic:3
Variant summary: BRCA1 c.4675G>A (p.Glu1559Lys) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. This sequence change occurs at the last nucleotide of exon 14. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a 5 splicing donor site. Consistent with these predications, a functional study report that this alteration activated a cryptic splice site resulting in the loss of the last 11 nucleotides of the exon 14 (Wappenschmidt_2012). The variant was absent in 251130 control chromosomes (gnomAD). c.4675G>A has been reported in the literature in individuals affected with Hereditary Breast and Ovarian Cancer Syndrome (Rebbeck_2018). These data indicate that the variant is likely to be associated with disease. Six ClinVar submitters including an expert panel (ENIGMA) cite the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 1559 of the BRCA1 protein (p.Glu1559Lys). RNA analysis indicates that this missense change induces altered splicing and may result in an absent or disrupted protein product. This variant is present in population databases (rs80356988, gnomAD 0.007%). This missense change has been observed in individual(s) with breast cancer and/or ovarian cancer (PMID: 17761984, 23239986, 24333842, 24797986, 25066507). It has also been observed to segregate with disease in related individuals. This variant is also known as c.4794G>A. ClinVar contains an entry for this variant (Variation ID: 37604). Based on a multifactorial likelihood algorithm using genetic, in silico, and/or statistical data, this variant has been determined to have a high probability of being pathogenic (PMID: 31131967). Experimental studies have shown that this missense change does not substantially affect BRCA1 function (PMID: 30765603). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this missense change results in deletion of the last 11 nucleotides of exon 14 (also known as exon 15) and introduces a premature termination codon (PMID: 23239986, 31143303; Invitae). The resulting mRNA is expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. -
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Hereditary cancer-predisposing syndrome Pathogenic:1
The c.4675G>A pathogenic mutation (also known as p.E1559K), located in coding exon 13 of the BRCA1 gene, results from a G to A substitution at nucleotide position 4675. The glutamic acid at codon 1559 is replaced by lysine, an amino acid with similar properties. However, this change occurs in the last base pair of coding exon 13, which makes it likely to have some effect on normal mRNA splicing. In vitro transcript analyses showed that this alteration activated a cryptic splice site leading to the loss of the last 11 nucleotides of the exon and causing a premature stop codon Wappenschmidt B et al. PLoS One. 2012;7(12):e50800; Wangensteen T et al. Hered Cancer Clin Pract, 2019 May;17:14). This alteration has been identified in individuals diagnosed with breast and/or ovarian cancer (Callahan MJ et al. J Clin Oncol. 2007 Sep 1;25(25):3985-90; Wappenschmidt B et al. PLoS One. 2012;7(12):e50800; Tihomirova L et al. Adv Med Sci. 2014 Mar;59(1):114-9; Conner JR et al. Gynecol Oncol. 2014 Feb;132(2):280-6; De Talhouet S et al. Sci Rep, 2020 04;10:7073). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site and will result in the creation or strengthening of a novel splice donor site. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at