rs1555460308

Positions:

• chr16-23629654-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 4P and 3B. PM1 PM2 BP4_Moderate BP6

The NM_024675.4(PALB2):​c.2500C>T​(p.His834Tyr) 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H834R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PALB2 NM_024675.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 0.111

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 1 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 15 uncertain in NM_024675.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.102838755).
• BP6: Variant 16-23629654-G-A is Benign according to our data. Variant chr16-23629654-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 490077.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=2, Likely_benign=1}. Variant chr16-23629654-G-A is described in Lovd as [Likely_benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PALB2	NM_024675.4	c.2500C>T	p.His834Tyr	missense_variant	5/13	ENST00000261584.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PALB2	ENST00000261584.9	c.2500C>T	p.His834Tyr	missense_variant	5/13	1	NM_024675.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Dec 05, 2023	This missense variant replaces histidine with tyrosine at codon 834 of the PALB2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with PALB2-related disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Apr 26, 2024	This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 02, 2023

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: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The tyrosine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. ClinVar contains an entry for this variant (Variation ID: 490077). This variant has not been reported in the literature in individuals affected with PALB2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces histidine, which is basic and polar, with tyrosine, which is neutral and polar, at codon 834 of the PALB2 protein (p.His834Tyr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.079
BayesDel_addAF	Benign	-0.34	T
BayesDel_noAF	Benign	-0.72
CADD	Benign	3.0
DANN	Benign	0.63
DEOGEN2	Benign	0.025	T;T
Eigen	Benign	-0.40
Eigen_PC	Benign	-0.54
FATHMM_MKL	Benign	0.12	N
LIST_S2	Benign	0.54	T;T
M_CAP	Benign	0.0073	T
MetaRNN	Benign	0.10	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.3	.;L
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.30	T
PROVEAN	Benign	-1.5	N;N
REVEL	Benign	0.046
Sift	Benign	0.42	T;T
Sift4G	Benign	0.88	T;T
Polyphen		0.95	.;P
Vest4		0.20
MutPred		0.23		.;Loss of disorder (P = 0.0795);
MVP		0.47
MPC		0.060
ClinPred		0.13	T
GERP RS		2.1
Varity_R		0.045
gMVP		0.16

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: rs1555460308; hg19: chr16-23640975;