rs780936436

Positions:

chr7-124863547-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2PP3_ModeratePP5

The NM_015450.3(POT1):c.349C>T(p.Arg117Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,660 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. R117H) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

POT1
NM_015450.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3U:1O:1

Conservation

PhyloP100: 5.86

Variant links:

Genes affected

POT1 (HGNC:17284): (protection of telomeres 1) This gene is a member of the telombin family and encodes a nuclear protein involved in telomere maintenance. Specifically, this protein functions as a member of a multi-protein complex that binds to the TTAGGG repeats of telomeres, regulating telomere length and protecting chromosome ends from illegitimate recombination, catastrophic chromosome instability, and abnormal chromosome segregation. Increased transcriptional expression of this gene is associated with stomach carcinogenesis and its progression. Alternatively spliced transcript variants have been described. [provided by RefSeq, Jul 2008]

POT1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.911

PP5

Variant 7-124863547-G-A is Pathogenic according to our data. Variant chr7-124863547-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 475082.We mark this variant Likely_pathogenic, oryginal submissions are: {not_provided=1, Likely_pathogenic=1, Pathogenic=1, Uncertain_significance=1}. Variant chr7-124863547-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
POT1	NM_015450.3 linkuse as main transcript	c.349C>T	p.Arg117Cys	missense_variant	8/19	ENST00000357628.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POT1	ENST00000357628.8 linkuse as main transcript	c.349C>T	p.Arg117Cys	missense_variant	8/19	2	NM_015450.3	P1	Q9NUX5-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251098

Hom.:

AF XY:

0.00000737

AC XY:

AN XY:

135690

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461660

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727132

show subpopulations

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.:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3Uncertain:1Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Tumor predisposition syndrome 3

Pathogenic:2Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 08, 2023	This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 117 of the POT1 protein (p.Arg117Cys). This variant is present in population databases (rs780936436, gnomAD 0.0009%). This missense change has been observed in individuals with clinical features of POT1 tumor predisposition syndrome (PMID: 26403419; Invitae). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 475082). 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) performed at Invitae indicates that this missense variant is not expected to disrupt POT1 protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change affects POT1 function (PMID: 26403419). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, no assertion criteria provided	clinical testing	Center of Human Genetics, Hôpital Erasme	-	The variant is rare in gnomADv4 (2/1461660 alleles, frequency : 0.00014%). Arginine at position 117 is an amino acid that appears to be highly conserved in evolution. The variant is located in the Telomeric single stranded DNA binding domain. The variant has been describred in 3 “Li-Fraumeni-like” families with multiple cancers including cardiosarcomas but also melanomas or lung cancers. In silico, in vitro and in vivo studies in cells showed that the variant reduces POT1 binding to telomeres and increases telomere length and fragility (PMID:26403419_2015). Another study by the same author showed the presence of a POT1 mutation in 20% of families with angiosarcomas and 10% of individuals with sporadic angio or cardiosarcoma (PMID:28853721_2017). The patient's phenotype and family history are compatible with the pathology associated with POT1 gene. -
not provided, no classification provided	literature only	GeneReviews	-	Reported in 3 families with Li-Fraumeni-like and familial cardiac angiosarcoma -

Hereditary cancer-predisposing syndrome

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 02, 2023

The p.R117C variant (also known as c.349C>T), located in coding exon 4 of the POT1 gene, results from a C to T substitution at nucleotide position 349. The arginine at codon 117 is replaced by cysteine, an amino acid with highly dissimilar properties. This alteration segregated in three Li-Fraumeni like families, including members affected with cardiac angiosarcomas, and other soft tissue sarcomas. Individuals in these families were shown to have reduced telomere bound POT1 levels, abnormally long telomeres, and increased telomere fragility (Calvete O et al. Nat Commun, 2015 Sep;6:8383). Mouse modeling using both embryonic fibroblasts and tissues with the R117C alteration showed longer telomeres than wild-type controls and complementation assays showed that R117C exerts dominant-negative effects at telomeres (Martínez P et al. PLoS Genet, 2022 06;18:e1010260). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Dec 17, 2020

Identified in Spanish families with angiosarcoma and other cancers (Calvete 2015); Published functional studies demonstrate reduced recruitment of POT1 protein to telomeres and increased DNA damage markers, but no impact on telomerase activity in patient cells (Calvete 2015, Calvete 2019); Not observed at a significant frequency in large population cohorts (Lek 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 26403419, 28853721, 32033110, 28389767, 31510873) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.30

BayesDel_addAF

Uncertain

0.12

BayesDel_noAF

Uncertain

-0.060

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.95

Eigen

Uncertain

0.67

Eigen_PC

Uncertain

0.61

FATHMM_MKL

Uncertain

0.94

LIST_S2

Uncertain

0.89

M_CAP

Uncertain

0.11

MetaRNN

Pathogenic

0.91

MetaSVM

Benign

-0.61

MutationAssessor

Uncertain

2.6

MutationTaster

Benign

1.0

D;D

PrimateAI

Uncertain

0.57

PROVEAN

Pathogenic

-4.5

REVEL

Uncertain

0.39

Sift

Uncertain

0.0010

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.81

MutPred

0.73

Loss of solvent accessibility (P = 0.0404);

MVP

0.67

MPC

2.3

ClinPred

0.99

GERP RS

4.6

Varity_R

0.40

gMVP

0.91

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over