chr16-23629693-T-A

Position:

• chr16-23629693-T-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_024675.4(PALB2):​c.2461A>T​(p.Asn821Tyr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,894 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: PALB2 NM_024675.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:7
• Conservation: PhyloP100: 0.320

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 Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.14586398).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PALB2	NM_024675.4	c.2461A>T	p.Asn821Tyr	missense_variant	5/13	ENST00000261584.9	NP_078951.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PALB2	ENST00000261584.9	c.2461A>T	p.Asn821Tyr	missense_variant	5/13	1	NM_024675.4	ENSP00000261584.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251472 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135916

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.0000992

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461894 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727248

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000765

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Oct 18, 2023	The p.N821Y variant (also known as c.2461A>T), located in coding exon 5 of the PALB2 gene, results from an A to T substitution at nucleotide position 2461. The asparagine at codon 821 is replaced by tyrosine, an amino acid with dissimilar properties. This alteration was reported as a VUS in one patient from a Romanian cohort of 130 patients who met NCCN criteria for HBOC testing who underwent MGPT (Goidescu IG et al. Clujul Med, 2018 Apr;91:157-165). This variant was identified in a cohort of 3,579 African males diagnosed with prostate cancer who underwent multi-gene panel testing of 19 DNA repair and cancer predisposition genes (Matejcic M et al. JCO Precis Oncol, 2020 Jan;4:32-43). This alteration was found to be functionally normal in a DNA-repair assay (Brnich SE et al. J Mol Diagn, 2021 Jul;23:847-864). This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jun 22, 2022	This missense variant replaces asparagine with tyrosine at codon 821 of the PALB2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). A functional study has reported that this variant has no impact on DNA repair activity (PMID: 33964450). This variant has been reported in one individual affected with breast cancer and in a breast cancer case-control meta-analysis in 1/60466 cases and 0/53461 unaffected individuals (PMID: 29785153, 33471991; Leiden Open Variation Database DB-ID PALB2_010894). This variant has been identified in 1/251472 chromosomes 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	GeneKor MSA	Aug 01, 2018	- -

not specified Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Mar 17, 2023	Variant summary: PALB2 c.2461A>T (p.Asn821Tyr) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251472 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.2461A>T has been reported in the literature in individuals with personal/family history of breast cancer (e.g. Goidescu_2018, Tsaousis_2019, Dorling_2021). These reports do not provide unequivocal conclusions about association of the variant with Hereditary Breast And Ovarian Cancer Syndrome. Experimental evidence from an in vitro Homologous Recombination/Non-Homologous End Joining assay showed that the variant had normal function (Brnich_2021). Four ClinVar submitters have assessed the variant since 2014: all classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Uncertain significance, no assertion criteria provided	clinical testing	Genetic Services Laboratory, University of Chicago	May 05, 2022	DNA sequence analysis of the PALB2 gene demonstrated a sequence change, c.2461A>T, in exon 5 that results in an amino acid change, p.Asn821Tyr. This sequence change has been described in the gnomAD database in one individual which corresponds to a population frequency of 0.00040% (dbSNP rs958566673). The p.Asn821Tyr change affects a moderately conserved amino acid residue located in a domain of the PALB2 protein that is not known to be functional. In-silico pathogenicity prediction tools (SIFT, PolyPhen2, Align GVGD, REVEL) provide contradictory results for the p.Asn821Tyr substitution. An experimental study demonstrate that this sequence change may lead reduced PALB2 activity compared to wild type (PMID: 33964450). This sequence change has been previously described in an individual with breast cancer and in an individual with a personal or family history of breast and/or ovarian cancer (PMID: 29785153, 31159747). Due to insufficient evidences, the clinical significance of the p.Asn821Tyr change remains unknown at this time. -

Familial cancer of breast Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Jul 07, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 09, 2024	This sequence change replaces asparagine, which is neutral and polar, with tyrosine, which is neutral and polar, at codon 821 of the PALB2 protein (p.Asn821Tyr). This variant is present in population databases (no rsID available, gnomAD 0.01%). This missense change has been observed in individual(s) with a personal and/or family history of breast and/or ovarian cancer (PMID: 29785153, 31159747). ClinVar contains an entry for this variant (Variation ID: 480228). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt PALB2 protein function with a negative predictive value of 80%. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Benign	-0.19	T
BayesDel_noAF	Benign	-0.51
CADD	Benign	19
DANN	Uncertain	0.99
DEOGEN2	Benign	0.077	T;T
Eigen	Benign	-0.13
Eigen_PC	Benign	-0.31
FATHMM_MKL	Benign	0.26	N
LIST_S2	Benign	0.67	T;T
M_CAP	Benign	0.024	T
MetaRNN	Benign	0.15	T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Uncertain	2.3	.;M
PrimateAI	Benign	0.33	T
PROVEAN	Uncertain	-3.5	D;D
REVEL	Benign	0.032
Sift	Uncertain	0.0050	D;D
Sift4G	Uncertain	0.023	D;D
Polyphen		0.99	.;D
Vest4		0.30
MutPred		0.20		.;Loss of loop (P = 0.0804);
MVP		0.45
MPC		0.35
ClinPred		0.67	D
GERP RS		2.6
Varity_R		0.23
gMVP		0.16

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs958566673; hg19: chr16-23641014;