rs1554420158

Positions:

• chr7-124841145-T-C

Variant summary

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

The NM_015450.3(POT1):​c.1197A>G​(p.Ile399Met) 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 Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: POT1 NM_015450.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: -0.311

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 (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=0.041994214).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POT1	NM_015450.3	c.1197A>G	p.Ile399Met	missense_variant	14/19	ENST00000357628.8	NP_056265.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POT1	ENST00000357628.8	c.1197A>G	p.Ile399Met	missense_variant	14/19	2	NM_015450.3	ENSP00000350249.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tumor predisposition syndrome 3 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 08, 2021

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. This variant has not been reported in the literature in individuals affected with POT1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces isoleucine with methionine at codon 399 of the POT1 protein (p.Ile399Met). The isoleucine residue is weakly conserved and there is a small physicochemical difference between isoleucine and methionine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 18, 2023

The p.I399M variant (also known as c.1197A>G), located in coding exon 10 of the POT1 gene, results from an A to G substitution at nucleotide position 1197. The isoleucine at codon 399 is replaced by methionine, an amino acid with highly similar properties. This amino acid position is conserved. 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	0.069
BayesDel_addAF	Benign	-0.33	T
BayesDel_noAF	Benign	-0.72
CADD	Benign	5.2
DANN	Benign	0.83
DEOGEN2	Benign	0.12	T;T;T
Eigen	Benign	-0.96
Eigen_PC	Benign	-0.99
FATHMM_MKL	Benign	0.041	N
LIST_S2	Benign	0.53	T;T;.
M_CAP	Benign	0.0097	T
MetaRNN	Benign	0.042	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.1	L;.;.
PrimateAI	Benign	0.23	T
PROVEAN	Benign	0.14	N;N;.
REVEL	Benign	0.014
Sift	Benign	0.15	T;T;.
Sift4G	Benign	0.29	T;T;T
Polyphen		0.20	B;.;.
Vest4		0.21
MutPred		0.26		Gain of catalytic residue at I399 (P = 0.0255);.;.;
MVP		0.45
MPC		0.085
ClinPred		0.044	T
GERP RS		0.034
Varity_R		0.16
gMVP		0.29

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: rs1554420158; hg19: chr7-124481199;