chr16-23641111-T-C

Position:

• chr16-23641111-T-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_024675.4(PALB2):​c.47A>G​(p.Lys16Arg) variant causes a missense, splice region 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. 3/3 splice prediction tools predicting alterations to normal splicing. 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. K16E) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PALB2 NM_024675.4 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 1.64

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 Pathogenic. Variant got 10 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 5 benign, 15 uncertain in NM_024675.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-23641111-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1713226.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PALB2	NM_024675.4	c.47A>G	p.Lys16Arg	missense_variant, splice_region_variant	1/13	ENST00000261584.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PALB2	ENST00000261584.9	c.47A>G	p.Lys16Arg	missense_variant, splice_region_variant	1/13	1	NM_024675.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

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	Feb 03, 2021	The p.K16R variant (also known as c.47A>G), located in coding exon 1 of the PALB2 gene, results from an A to G substitution at nucleotide position 47. The lysine at codon 16 is replaced by arginine, an amino acid with highly similar properties. This amino acid position is highly 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	Aug 11, 2018	- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 18, 2016

This variant is denoted PALB2 c.47A>G at the cDNA level, p.Lys16Arg (K16R) at the protein level, and results in the change of a Lysine to an Arginine (AAG>AGG). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. PALB2 Lys16Arg was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Since Lysine and Arginine share similar properties, this is considered a conservative amino acid substitution. PALB2 Lys16Arg occurs at a position where amino acids with properties similar to Lysine are tolerated across species and is located in a DNA binding region, a region of interaction with BRCA1 and RAD51, as well as a region required for PALB2 oligomerization and important for focal concentration at DNA damage sites (UniProt). While protein-based in silico analyses are inconsistent regarding the effect this variant may have on protein structure and function, multiple splicing models predict this variant may destroy the nearby natural splice donor site and lead to abnormal splicing. However, in the absence of RNA or functional studies, the actual effect of this variant is unknown. Based on currently available evidence, it is unclear whether PALB2 Lys16Arg is pathogenic or benign. We consider it to be a variant of uncertain significance. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 27, 2022

This sequence change replaces lysine, which is basic and polar, with arginine, which is basic and polar, at codon 16 of the PALB2 protein (p.Lys16Arg). 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. Studies have shown that this missense change alters mRNA splicing and is expected to lead to the loss of protein expression (PMID: 34846068). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 422035). This missense change has been observed in individual(s) with breast cancer (PMID: 34846068). This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.24	T
BayesDel_noAF	Benign	-0.58
CADD	Pathogenic	34
DANN	Uncertain	1.0
DEOGEN2	Benign	0.22	T
Eigen	Benign	0.12
Eigen_PC	Benign	0.15
FATHMM_MKL	Benign	0.44	N
LIST_S2	Benign	0.67	T
M_CAP	Benign	0.0065	T
MetaRNN	Benign	0.19	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Uncertain	2.7	M
MutationTaster	Benign	0.94	N
PrimateAI	Uncertain	0.70	T
PROVEAN	Benign	-1.4	N
REVEL	Benign	0.059
Sift	Uncertain	0.018	D
Sift4G	Benign	0.10	T
Polyphen		0.70	P
Vest4		0.34
MutPred		0.13		Gain of ubiquitination at K14 (P = 0.0401);
MVP		0.46
MPC		0.32
ClinPred		0.93	D
GERP RS		3.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.089
gMVP		0.028

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		0.92		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.92		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1064795514; hg19: chr16-23652432; COSMIC: COSV55162534; COSMIC: COSV55162534;