chr7-124853125-A-C

Position:

• chr7-124853125-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_015450.3(POT1):​c.716T>G​(p.Leu239Arg) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. L239L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: POT1 NM_015450.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.14

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.913

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
POT1	NM_015450.3	c.716T>G	p.Leu239Arg	missense_variant	10/19	ENST00000357628.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POT1	ENST00000357628.8	c.716T>G	p.Leu239Arg	missense_variant	10/19	2	NM_015450.3	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tumor predisposition syndrome 3 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 17, 2020

In summary, this variant has uncertain impact on POT1 function. The available evidence is currently insufficient to determine its role 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 disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with a POT1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces leucine with arginine at codon 239 of the POT1 protein (p.Leu239Arg). The leucine residue is highly conserved and there is a moderate physicochemical difference between leucine and arginine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Pathogenic	0.14
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D;D
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.87	D;D
M_CAP	Benign	0.049	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Uncertain	-0.23	T
MutationAssessor	Uncertain	2.7	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.56	T
PROVEAN	Uncertain	-3.5	D;D
REVEL	Uncertain	0.55
Sift	Uncertain	0.0010	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;.
Vest4		0.89
MutPred		0.73		Loss of sheet (P = 0.0181);.;
MVP		0.72
MPC		2.3
ClinPred		0.99	D
GERP RS		6.1
Varity_R		0.91
gMVP		0.98

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: rs1554424050; hg19: chr7-124493179;