chr16-23635980-C-T

Position:

• chr16-23635980-C-T

Variant summary

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

The ENST00000261584.9(PALB2):​c.566G>A​(p.Arg189Lys) 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. 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. R189I) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PALB2 ENST00000261584.9 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: -1.09

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 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.10754368).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PALB2	NM_024675.4	c.566G>A	p.Arg189Lys	missense_variant	4/13	ENST00000261584.9	NP_078951.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PALB2	ENST00000261584.9	c.566G>A	p.Arg189Lys	missense_variant	4/13	1	NM_024675.4	ENSP00000261584	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 12, 2019

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 output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The lysine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with PALB2-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with lysine at codon 189 of the PALB2 protein (p.Arg189Lys). The arginine residue is moderately conserved and there is a small physicochemical difference between arginine and lysine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 12, 2022

The p.R189K variant (also known as c.566G>A), located in coding exon 4 of the PALB2 gene, results from a G to A substitution at nucleotide position 566. The arginine at codon 189 is replaced by lysine, an amino acid with highly similar properties. This amino acid position is conserved. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.086
BayesDel_addAF	Benign	-0.32	T
BayesDel_noAF	Benign	-0.70
CADD	Benign	0.26
DANN	Benign	0.59
DEOGEN2	Benign	0.13	T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.3
FATHMM_MKL	Benign	0.023	N
LIST_S2	Benign	0.44	T
M_CAP	Benign	0.012	T
MetaRNN	Benign	0.11	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.1	L
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.19	T
PROVEAN	Benign	-0.19	N
REVEL	Benign	0.028
Sift	Benign	0.31	T
Sift4G	Benign	0.38	T
Polyphen		0.0020	B
Vest4		0.042
MutPred		0.26		Gain of ubiquitination at R189 (P = 7e-04);
MVP		0.21
MPC		0.053
ClinPred		0.064	T
GERP RS		-4.4
Varity_R		0.032
gMVP		0.10

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: rs764180110; hg19: chr16-23647301;