16-23636336-T-G

Variant names:

• chr16-23636336-T-G
• rs730881879
• NM_024675.4:c.212-2A>C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PVS1_Strong PM2 PP5

The NM_024675.4(PALB2):​c.212-2A>C variant causes a splice acceptor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000697 in 1,434,974 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:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: PALB2 NM_024675.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4 U:1
• Conservation: PhyloP100: 3.12

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 Likely_pathogenic. Variant got 7 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.41364786 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.7, offset of -36, new splice context is: tttttgttttattttataAGaaa. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-23636336-T-G is Pathogenic according to our data. Variant chr16-23636336-T-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 640795.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Pathogenic=2, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PALB2	NM_024675.4	c.212-2A>C		splice_acceptor_variant, intron_variant	Intron 3 of 12	ENST00000261584.9	NP_078951.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PALB2	ENST00000261584.9	c.212-2A>C		splice_acceptor_variant, intron_variant	Intron 3 of 12	1	NM_024675.4	ENSP00000261584.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.97e-7 AC: 1 AN: 1434974 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 713020

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.12e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Familial cancer of breast Pathogenic:3

Jan 01, 2019

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was identified as compound heterozygous. -

Oct 31, 2023

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 17, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. 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 disrupted protein product. This variant is not present in population databases (gnomAD no frequency). 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: 640795). 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; Invitae). -

not provided Pathogenic:1

Oct 23, 2020

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Oct 12, 2020

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.212-2A>C intronic variant results from an A to C substitution two nucleotides upstream from coding exon 4 in the PALB2 gene. 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. The resulting transcript is predicted to be in-frame and is not expected to trigger nonsense-mediated mRNAdecay; however, direct evidence is unavailable. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Uncertain	-0.010
CADD	Pathogenic	27
DANN	Benign	0.97
Eigen	Pathogenic	0.85
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.98	D
GERP RS		5.6

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.80
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.45		Position offset: -34
DS_AL_spliceai		0.99		Position offset: -2

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

Publications

LitVar

Other links and lift over

dbSNP: rs730881879; hg19: chr16-23647657;