16-23637849-C-T

Position:

• chr16-23637849-C-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_024675.4(PALB2):​c.211+1G>A variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. 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 Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: PALB2 NM_024675.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 3.84

Genes affected

PALB2 (HGNC:26144): (partner and localizer of BRCA2) This gene encodes a protein that may function in tumor suppression. This protein binds to and colocalizes with the breast cancer 2 early onset protein (BRCA2) in nuclear foci and likely permits the stable intranuclear localization and accumulation of BRCA2. [provided by RefSeq, Jul 2008]

PALB2 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.02864364 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7.9, offset of 48, new splice context is: cagGTatat. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-23637849-C-T is Pathogenic according to our data. Variant chr16-23637849-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 492177.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PALB2	NM_024675.4	c.211+1G>A		splice_donor_variant, intron_variant		ENST00000261584.9	NP_078951.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PALB2	ENST00000261584.9	c.211+1G>A		splice_donor_variant, intron_variant		1	NM_024675.4	ENSP00000261584.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial cancer of breast Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Mendelics	May 28, 2019	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 17, 2023	This sequence change affects a donor splice site in intron 3 of the PALB2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in PALB2 are known to be pathogenic (PMID: 17200668, 17200671, 17200672, 24136930, 25099575). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with breast cancer (PMID: 32068069, 33811135). ClinVar contains an entry for this variant (Variation ID: 492177). Studies have shown that disruption of this splice site is associated with inconclusive levels of altered splicing (PMID: 34846068). 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. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Feb 07, 2024	- -

Hereditary cancer-predisposing syndrome Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Jun 14, 2024	The c.211+1G>A intronic variant results from a G to A substitution one nucleotide after coding exon 3 of the PALB2 gene. This alteration was identified in a cohort of 1338 Chinese high-risk breast cancer patients (Kwong A et al. J Mol Diagn, 2020 Apr;22:544-554). 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; however, direct evidence is insufficient at this time (Ambry internal data). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). 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. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Mar 19, 2020	This variant causes a G to A nucleotide substitution at the +1 position of intron 3 of the PALB2 gene. Splice site prediction tools suggest that this variant may have a significant impact on RNA splicing. Although this prediction has not been confirmed in published RNA studies, this variant is expected to result in an absent or disrupted protein product. This variant has been reported in individuals affected with breast cancer (PMID: 32068069). This variant has not been identified 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. -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Dec 01, 2022

Canonical splice site variant demonstrated via mini-gene assay to result in aberrant splicing creating two different transcripts: one predicted to cause a null allele and another leading to an in-frame product (Valenzuela-Palomo et al., 2022); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports a deleterious effect on splicing; Observed in individuals with breast cancer (Kwong et al., 2020); This variant is associated with the following publications: (PMID: 31589614, 32068069, 34846068) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Uncertain	0.060
CADD	Pathogenic	33
DANN	Uncertain	0.98
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Uncertain	0.97	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.90
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.55		Position offset: -47
DS_DL_spliceai		1.0		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555462026; hg19: chr16-23649170;