16-23626235-C-G

Variant names:

• chr16-23626235-C-G
• rs753153576
• NM_024675.4:c.2748+1G>C

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.2748+1G>C 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: 31)
• Consequence: PALB2 NM_024675.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 3.65

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]

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 0.04549284 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-23626235-C-G is Pathogenic according to our data. Variant chr16-23626235-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 372056.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PALB2	NM_024675.4	c.2748+1G>C		splice_donor_variant, intron_variant	Intron 7 of 12	ENST00000261584.9	NP_078951.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PALB2	ENST00000261584.9	c.2748+1G>C		splice_donor_variant, intron_variant	Intron 7 of 12	1	NM_024675.4	ENSP00000261584.4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic/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	KCCC/NGS Laboratory, Kuwait Cancer Control Center	Jul 05, 2023	This sequence change affects a donor splice site in intron 7 of the PALB2 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. 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: 28825143, 30720863, 31263054, 31841383). ClinVar contains an entry for this variant (Variation ID: 372056). Studies have shown that disruption of this splice site results in skipping of exon 7, but is expected to preserve the integrity of the reading-frame (PMID: 30890586). This variant disrupts the WD40-like repeats of the PALB2 protein, which are required for interactions with the BRCA2, POLH, and RAD51C proteins (PMID: 24141787, 24485656). While functional studies have not been performed to directly test the effect of this variant on PALB2 protein function, this suggests that disruption of this region of the protein is causative of disease. 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. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Aug 28, 2023	This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 7 of the PALB2 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. ClinVar contains an entry for this variant (Variation ID: 372056). Disruption of this splice site has been observed in individual(s) with breast cancer (PMID: 28825143, 30720863, 31263054, 31841383). For these reasons, this variant has been classified as Pathogenic. Other variant(s) that result in loss of exon 7 have been determined to be pathogenic (Invitae). This suggests that this variant may also be clinically significant and likely to be disease-causing. Studies have shown that disruption of this splice site results in skipping of exon 7, but is expected to preserve the integrity of the reading-frame (PMID: 30890586). -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Nov 02, 2016	- -

Breast-ovarian cancer, familial, susceptibility to, 5 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

KCCC/NGS Laboratory, Kuwait Cancer Control Center

Jul 07, 2023

This sequence change affects a donor splice site in intron 7 of the PALB2 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. 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: 28825143, 30720863, 31263054, 31841383). ClinVar contains an entry for this variant (Variation ID: 372056). Studies have shown that disruption of this splice site results in skipping of exon 7, but is expected to preserve the integrity of the reading-frame (PMID: 30890586). This variant disrupts the WD40-like repeats of the PALB2 protein, which are required for interactions with the BRCA2, POLH, and RAD51C proteins (PMID: 24141787, 24485656). While functional studies have not been performed to directly test the effect of this variant on PALB2 protein function, this suggests that disruption of this region of the protein is causative of disease. 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. -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Apr 21, 2023

The PALB2 c.2748+1G>C variant disrupts a canonical splice-donor site and is predicted to interfere with normal PALB2 mRNA splicing. The resulting exon 7 skipping maintains the translational reading frame, but disrupts the WD40 protein domain involved in BRCA2-binding and DNA damage repair (PMIDs: 19423707 (2009), 17420451 (2007)). This variant has not been reported in the published literature. It also has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). Two other variants affecting this splice site, c.2748+1G>T and c.2748+1G>A, have been reported as deleterious in individuals with breast and ovarian cancer (PMIDs: 34282249 (2021), 32546565 (2021), 28888541 (2017), 28825143 (2017)). Based on the available information, the c.2748+1G>C variant is classified as likely pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Mar 16, 2022

This variant causes a G to C nucleotide substitution at the +1 position of intron 7 of the PALB2 gene. Splice site prediction tools predict 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 not been reported in individuals affected with hereditary cancer in the literature. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Uncertain	0.070
CADD	Pathogenic	27
DANN	Uncertain	0.99
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Uncertain	0.93	D
GERP RS		5.7
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	0.86
SpliceAI score (max)		0.73		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.73		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: rs753153576; hg19: chr16-23637556;