16-23636336-T-C
Variant summary
Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PVS1_StrongPP5
The NM_024675.4(PALB2):c.212-2A>G variant causes a splice acceptor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000441 in 1,586,880 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_024675.4 splice_acceptor, intron
Scores
Clinical Significance
Conservation
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ACMG classification
Our verdict: Uncertain_significance. The variant received 5 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000197 AC: 3AN: 151906Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.00000452 AC: 1AN: 221342 AF XY: 0.00 show subpopulations
GnomAD4 exome AF: 0.00000279 AC: 4AN: 1434974Hom.: 0 Cov.: 29 AF XY: 0.00000421 AC XY: 3AN XY: 713020 show subpopulations
GnomAD4 genome AF: 0.0000197 AC: 3AN: 151906Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74194 show subpopulations
ClinVar
Submissions by phenotype
Familial cancer of breast Pathogenic:3Benign:1
This sequence change affects an acceptor splice site in intron 3 of the PALB2 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or altered protein product. This variant is present in population databases (rs730881879, gnomAD 0.001%). Disruption of this splice site has been observed in individual(s) with breast cancer (PMID: 26681312). ClinVar contains an entry for this variant (Variation ID: 182757). Studies have shown that disruption of this splice site alters mRNA splicing and is expected to lead to the loss of protein expression (PMID: 30890586; internal data). For these reasons, this variant has been classified as Pathogenic. -
This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
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This variant is considered likely benign. This variant is intronic and is not expected to impact mRNA splicing. This variant is strongly associated with less severe personal and family histories of cancer, typical for individuals without pathogenic variants in this gene [PMID: 25085752]. -
not provided Pathogenic:3
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This test has identified one copy of the c.212-2A>G variant in the PALB2 gene. This variant is located in a canonical splice-acceptor site and interferes with normal PALB2 mRNA splicing. The variant has been reported in an individual with breast cancer in the published literature (PMID: 26681312 (2015)). Based on the available information, this variant is classified as pathogenic. -
Canonical splice site variant predicted to result in an in-frame loss of the adjacent exon in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 38061684, 31589614, 30293905, 32172797, 35626031, 26681312, 30890586) -
Hereditary cancer-predisposing syndrome Pathogenic:2
This variant causes an A>G nucleotide substitution at the -2 position of intron 3 of the PALB2 gene. Splice site prediction tools predict that this variant may have a significant impact on RNA splicing. A minigene splicing assay reported that a similar canonical splice acceptor site variant in intron 3, c.212-1G>A, resulted in the out-of-frame skipping of exon 4 and exon 5 (PMID: 30890586). This variant has been reported in two individuals affected with breast and/or ovarian cancer (PMID: 26681312, 35626031). This variant has been identified in 1/221342 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Loss of PALB2 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Likely Pathogenic. -
The c.212-2A>G intronic variant results from an A to G substitution two nucleotides upstream from coding exon 4 in the PALB2 gene. This alteration has been identified in multiple individuals with a personal history of breast and/or ovarian cancer (Susswein LR et al. Genet. Med. 2016 08;18:823-32; Espinel W et al. Cancers (Basel), 2022 May;14:). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site and may result in the creation or strengthening of a novel splice acceptor site; however, direct evidence is insufficient at this time (Ambry internal data). Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as likely pathogenic. -
Familial cancer of breast;C1835817:Fanconi anemia complementation group N;C3150547:Pancreatic cancer, susceptibility to, 3 Pathogenic:1
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PALB2-related disorder Pathogenic:1
The PALB2 c.212-2A>G variant is predicted to disrupt the AG splice acceptor site and interfere with normal splicing. This variant has been reported in patients with a personal history of breast and/or ovarian cancer (Table S1, Susswein et al. 2016. PubMed ID: 26681312; Table S2, Espinel et al. 2022. PubMed ID: 35626031; Infante et al. 2024. PubMed ID: 38061684). Of note, a minigene splicing assay has shown that a similar canonical splice acceptor site variant c.212-1G>A leads to a skipping of exon 4 and 5 (Lopez-Perolio et al. 2019. PubMed ID: 30890586). The c.212-2A>G variant is reported in 0.0010% of alleles in individuals of European (non-Finnish) descent in gnomAD. This variant has been interpreted as likely pathogenic and pathogenic by multiple labs in the ClinVar database (https://www.ncbi.nlm.nih.gov/clinvar/variation/182757/). Variants that disrupt the consensus splice acceptor site in PALB2 are expected to be pathogenic. This variant is interpreted as likely pathogenic. -
Fanconi anemia complementation group N Pathogenic:1
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Hereditary breast ovarian cancer syndrome Pathogenic:1
Variant summary: PALB2 c.212-2A>G is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing and loss of PALB2 function. Several computational tools predict a significant impact on normal splicing: All predict the variant abolishes the canonical 3' acceptor site. At least one publication reports experimental evidence that disruption of this splice site induces altered splicing and may result in an absent or disrupted protein product (PMID 30890586). The variant allele was found at a frequency of 4.5e-06 in 221342 control chromosomes. c.212-2A>G has been reported in the literature in at-least two individuals affected with Hereditary Breast And Ovarian Cancer Syndrome (Susswein_2015, Espinel_2022). These data indicate that the variant may be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 35626031, 26681312, Internal data). ClinVar contains an entry for this variant (Variation ID: 182757). Based on the evidence outlined above, the variant was classified as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at