chr16-23630376-T-C

Position:

• chr16-23630376-T-C

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The ENST00000261584.9(PALB2):​c.1778A>G​(p.His593Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,782 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H593Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: PALB2 ENST00000261584.9 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: -2.57

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_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.05078572).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PALB2	NM_024675.4	c.1778A>G	p.His593Arg	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.1778A>G	p.His593Arg	missense_variant	5/13	1	NM_024675.4	ENSP00000261584	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461782 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727202

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000756

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

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, no assertion criteria provided	curation	Leiden Open Variation Database	Oct 10, 2018	Curators: Marc Tischkowitz, Arleen D. Auerbach. Submitter to LOVD: Yukihide Momozawa. -
Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Oct 18, 2022	It has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). In the published literature, the variant has been reported in individuals with breast cancer as well as in unaffected individuals (PMID: 30287823 (2018)). Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is benign. Based on the available information, we are unable to determine the clinical significance of this variant. -

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jun 21, 2021	This missense variant replaces histidine with arginine at codon 593 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). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in a breast cancer case-control study in 3/7051 female cases and in 10/11241 unaffected females with OR=0.3984 (95% CI 0.1-1.5) and absent in male cases and in 3/12490 unaffected males (PMID: 30287823). This variant also has been reported in 5/7636 prostate cancer cases and 3/12366 unaffected individuals and in 0/1005 pancreatic cancer cases and 13/23705 unaffected individuals (PMID: 31214711, 32980694). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Although there is a suspicion that this variant may not be associated with disease, additional studies are necessary 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	May 31, 2023	The p.H593R variant (also known as c.1778A>G), located in coding exon 5 of the PALB2 gene, results from an A to G substitution at nucleotide position 1778. The histidine at codon 593 is replaced by arginine, an amino acid with highly similar properties. This alteration was observed with an allele frequency of 0.00043 in 7,051 unselected female breast cancer patients and was observed with an allele frequency of 0.00089 in 11,241 female controls of Japanese ancestry. In addition, it was not observed in unselected male breast cancer patients and was observed with an allele frequency of 0.0002 in 12490 male controls of Japanese ancestry (Momozawa Y et al. Nat Commun, 2018 10;9:4083). 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. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 25, 2024

This sequence change replaces histidine, which is basic and polar, with arginine, which is basic and polar, at codon 593 of the PALB2 protein (p.His593Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with breast cancer (PMID: 30287823). ClinVar contains an entry for this variant (Variation ID: 439231). 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	0.068
BayesDel_addAF	Benign	-0.38	T
BayesDel_noAF	Benign	-0.79
CADD	Benign	0.0060
DANN	Benign	0.17
DEOGEN2	Benign	0.019	T;T
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.5
FATHMM_MKL	Benign	0.071	N
LIST_S2	Benign	0.39	T;T
M_CAP	Benign	0.0049	T
MetaRNN	Benign	0.051	T;T
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	1.3	.;L
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.29	T
PROVEAN	Benign	-2.2	N;N
REVEL	Benign	0.020
Sift	Benign	0.38	T;T
Sift4G	Benign	0.46	T;T
Polyphen		0.010	.;B
Vest4		0.11
MutPred		0.33		.;Loss of helix (P = 0.0558);
MVP		0.17
MPC		0.064
ClinPred		0.082	T
GERP RS		-4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.044
gMVP		0.076

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: rs1555460654; hg19: chr16-23641697;