16-23636020-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 4P and 4B. PM1 PM2 BP4_Strong

The NM_024675.4(PALB2):c.526C>G(p.Leu176Val) 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. L176I) 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:2
• Conservation: PhyloP100: -0.393

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.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 16 uncertain in NM_024675.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.03610149).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PALB2	NM_024675.4	c.526C>G	p.Leu176Val	missense_variant	4/13	ENST00000261584.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PALB2	ENST00000261584.9	c.526C>G	p.Leu176Val	missense_variant	4/13	1	NM_024675.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251450 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135896

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

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 Cov.: 33

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

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

Invitae

Dec 20, 2017

This variant is not present in population databases (ExAC no frequency). This sequence change replaces leucine with valine at codon 176 of the PALB2 protein (p.Leu176Val). The leucine residue is moderately conserved and there is a small physicochemical difference between leucine and valine. This variant has not been reported in the literature in individuals with PALB2-related disease. 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, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 18, 2022

The p.L176V variant (also known as c.526C>G), located in coding exon 4 of the PALB2 gene, results from a C to G substitution at nucleotide position 526. The leucine at codon 176 is replaced by valine, 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	0.099
BayesDel_addAF	Benign	-0.36	T
BayesDel_noAF	Benign	-0.59
Cadd	Benign	7.9
Dann	Benign	0.92
DEOGEN2	Benign	0.13	T
Eigen	Benign	-0.73
Eigen_PC	Benign	-0.81
FATHMM_MKL	Benign	0.097	N
LIST_S2	Benign	0.61	T
M_CAP	Benign	0.016	T
MetaRNN	Benign	0.036	T
MetaSVM	Benign	-0.98	T
MutationAssessor	Benign	1.8	L
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.25	T
PROVEAN	Benign	-0.67	N
REVEL	Benign	0.043
Sift	Benign	0.32	T
Sift4G	Benign	0.21	T
Polyphen		0.18	B
Vest4		0.096
MutPred		0.099		Gain of methylation at K177 (P = 0.0335);
MVP		0.22
MPC		0.068
ClinPred		0.062	T
GERP RS		0.16
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.034
gMVP		0.070

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: rs1211622922; hg19: chr16-23647341;