rs876659843

Positions:

• chr16-23641106-G-A
• chr16-23641106-G-C
• chr16-23641106-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_024675.4(PALB2):​c.48+4C>T variant causes a splice donor region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000197 in 152,182 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: 𝑓 0.000020 (0 hom., cov: 32)
• Consequence: PALB2 NM_024675.4 splice_donor_region, intron
• Scores: Splicing: ADA: 0.9925
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 3.26

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 Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PALB2	NM_024675.4	c.48+4C>T		splice_donor_region_variant, intron_variant		ENST00000261584.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PALB2	ENST00000261584.9	c.48+4C>T		splice_donor_region_variant, intron_variant		1	NM_024675.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152182 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000724

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152182 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74332

Gnomad4 AFR AF: 0.0000724

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Feb 07, 2023	This variant causes a C to T nucleotide substitution at the +4 position of intron 1 of the PALB2 gene. Splice site prediction tools are inconclusive regarding the impact of this variant on RNA splicing. A minigene splicing assay reported that this variant produced mainly full-length transcript (94.5%) and a small fraction of out-of-frame splicing product (5.5%) (PMID: 34846068). This variant was reported to be detected among the Breast Cancer After Diagnostic Gene Sequencing (BRIDGES) project (https://bridges-research.eu/) comprising of breast cancer cases and unaffected control individuals, however, the cancer health history of the carrier(s) was not disclosed (PMID: 34846068). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jun 22, 2015	The c.48+4C>T intronic variant results from a C to T substitution 4 nucleotides after coding exon 1 in the PALB2 gene. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. To date, this alteration has been detected with an allele frequency of approximately 0.002% (greater than 130000 alleles tested) in our clinical cohort. This nucleotide position is highly conserved in available vertebrate species. Using the BDGP and ESEfinder splice site prediction tools, this alteration is not predicted to have any significant effect on this donor splice site; however, direct evidence is unavailable. Since supporting evidence is limited at this time, the clinical significance of c.48+4C>T remains unclear. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 12, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This sequence change falls in intron 1 of the PALB2 gene. It does not directly change the encoded amino acid sequence of the PALB2 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (no rsID available, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with PALB2-related conditions. ClinVar contains an entry for this variant (Variation ID: 232567). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant does not affect mRNA splicing (PMID: 34846068). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.27
CADD	Benign	21
DANN	Benign	0.97
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Pathogenic	0.88
SpliceAI score (max)		0.14		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: rs876659843; hg19: chr16-23652427;