rs1555461163

chr16-23634882-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_024675.4(PALB2):c.1664A>G(p.Lys555Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 14/20 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. K555N) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PALB2 NM_024675.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 1.73

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 2 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 17 uncertain in NM_024675.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.1830788).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PALB2	NM_024675.4	c.1664A>G	p.Lys555Arg	missense_variant	4/13	ENST00000261584.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PALB2	ENST00000261584.9	c.1664A>G	p.Lys555Arg	missense_variant	4/13	1	NM_024675.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

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	Ambry Genetics	Aug 29, 2017	The p.K555R variant (also known as c.1664A>G), located in coding exon 4 of the PALB2 gene, results from an A to G substitution at nucleotide position 1664. The lysine at codon 555 is replaced by arginine, an amino acid with highly similar properties. 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	Feb 15, 2021	This missense variant replaces lysine with arginine at codon 555 of the PALB2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. 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). 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. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 29, 2021

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. ClinVar contains an entry for this variant (Variation ID: 484243). This variant has not been reported in the literature in individuals affected with PALB2-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces lysine with arginine at codon 555 of the PALB2 protein (p.Lys555Arg). The lysine residue is moderately conserved and there is a small physicochemical difference between lysine and arginine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.098
BayesDel_addAF	Benign	-0.30	T
BayesDel_noAF	Benign	-0.67
Cadd	Benign	13
Dann	Benign	0.85
DEOGEN2	Benign	0.023	T;T
Eigen	Benign	-0.62
Eigen_PC	Benign	-0.71
FATHMM_MKL	Benign	0.067	N
LIST_S2	Benign	0.40	T;T
M_CAP	Benign	0.017	T
MetaRNN	Benign	0.18	T;T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-0.81	N;N
Sift	Benign	0.053	T;T
Sift4G	Benign	0.49	T;T
Polyphen		0.57	.;P
Vest4		0.26
MutPred		0.24		.;Loss of methylation at K555 (P = 0.0177);
MVP		0.45
MPC		0.050
ClinPred		0.15	T
GERP RS		2.6
Varity_R		0.032
gMVP		0.16

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1555461163; hg19: chr16-23646203;