chr16-23635494-G-C

Position:

• chr16-23635494-G-C

Variant summary

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

The NM_024675.4(PALB2):​c.1052C>G​(p.Thr351Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,722 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: PALB2 NM_024675.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: -0.00400

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]

PALB2 (HGNC:):

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=0.06670499).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PALB2	NM_024675.4	c.1052C>G	p.Thr351Arg	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.1052C>G	p.Thr351Arg	missense_variant	4/13	1	NM_024675.4	ENSP00000261584.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461722 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727164

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jun 20, 2018

This variant is denoted PALB2 c.1052C>G at the cDNA level, p.Thr351Arg (T351R) at the protein level, and results in the change of a Threonine to an Arginine (ACA>AGA). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. PALB2 Thr351Arg was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Since Threonine and Arginine differ in some properties, this is considered a semi-conservative amino acid substitution. PALB2 Thr351Arg occurs at a position that is not conserved and is located in the DNA-binding region (UniProt). In silico analyses are inconsistent regarding the effect this variant may have on protein structure and function. Based on currently available information, it is unclear whether PALB2 Thr351Arg is pathogenic or benign. We consider it to be a variant of uncertain significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 13, 2023

The p.T351R variant (also known as c.1052C>G), located in coding exon 4 of the PALB2 gene, results from a C to G substitution at nucleotide position 1052. The threonine at codon 351 is replaced by arginine, an amino acid with similar properties. This amino acid position is poorly 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

Aug 17, 2023

This sequence change replaces threonine, which is neutral and polar, with arginine, which is basic and polar, at codon 351 of the PALB2 protein (p.Thr351Arg). 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: 419253). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on PALB2 protein function. 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	0.12
BayesDel_addAF	Benign	-0.26	T
BayesDel_noAF	Benign	-0.61
CADD	Benign	18
DANN	Uncertain	0.98
DEOGEN2	Benign	0.030	T;T
Eigen	Benign	-0.88
Eigen_PC	Benign	-0.91
FATHMM_MKL	Benign	0.10	N
LIST_S2	Benign	0.75	T;T
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.067	T;T
MetaSVM	Benign	-0.98	T
MutationAssessor	Benign	1.6	.;L
PrimateAI	Benign	0.28	T
PROVEAN	Benign	-1.6	N;N
REVEL	Benign	0.054
Sift	Uncertain	0.010	D;D
Sift4G	Uncertain	0.020	D;D
Polyphen		0.091	.;B
Vest4		0.17
MutPred		0.14		.;Loss of phosphorylation at T351 (P = 0.0605);
MVP		0.21
MPC		0.29
ClinPred		0.24	T
GERP RS		-1.5
Varity_R		0.11
gMVP		0.24

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: rs876658656; hg19: chr16-23646815;