16-23636041-G-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.505C>G(p.Leu169Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,880 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 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. L169I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: PALB2 NM_024675.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.999

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 3 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=0.13845485).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PALB2	NM_024675.4	c.505C>G	p.Leu169Val	missense_variant	4/13	ENST00000261584.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PALB2	ENST00000261584.9	c.505C>G	p.Leu169Val	missense_variant	4/13	1	NM_024675.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461880 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727240

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

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

Invitae

Aug 16, 2023

This sequence change replaces leucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 169 of the PALB2 protein (p.Leu169Val). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with PALB2-related conditions. ClinVar contains an entry for this variant (Variation ID: 484170). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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

Jan 18, 2016

The p.L169V variant (also known as c.505C>G), located in coding exon 4 of the PALB2 gene, results from a C to G substitution at nucleotide position 505. The leucine at codon 169 is replaced by valine, an amino acid with highly similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6497 samples (12994 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.001% (greater than 130000 alleles tested) in our clinical cohort. This amino acid position is 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Benign	-0.48
Cadd	Benign	19
Dann	Uncertain	1.0
DEOGEN2	Benign	0.30	T
Eigen	Benign	-0.076
Eigen_PC	Benign	-0.25
FATHMM_MKL	Benign	0.20	N
LIST_S2	Benign	0.77	T
M_CAP	Benign	0.026	D
MetaRNN	Benign	0.14	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Uncertain	2.7	M
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.25	T
PROVEAN	Benign	-1.7	N
REVEL	Benign	0.080
Sift	Uncertain	0.028	D
Sift4G	Benign	0.076	T
Polyphen		0.97	D
Vest4		0.10
MutPred		0.15		Loss of helix (P = 0.028);
MVP		0.30
MPC		0.31
ClinPred		0.54	D
GERP RS		3.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.11
gMVP		0.11

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: rs180177086; hg19: chr16-23647362;