rs771968149

Positions:

• chr7-124825277-CAT-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_015450.3(POT1):​c.1765_1766delAT​(p.Met589fs) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,456,184 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: POT1 NM_015450.3 frameshift
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.31

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 Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0735 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POT1	NM_015450.3	c.1765_1766delAT	p.Met589fs	frameshift_variant	18/19	ENST00000357628.8	NP_056265.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POT1	ENST00000357628.8	c.1765_1766delAT	p.Met589fs	frameshift_variant	18/19	2	NM_015450.3	ENSP00000350249.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000806 AC: 2 AN: 247990 Hom.: 0 AF XY: 0.00000746 AC XY: 1 AN XY: 134000

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000590

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1456184 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 724250

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000451

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

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

Nov 02, 2023

This sequence change creates a premature translational stop signal (p.Met589Valfs*9) in the POT1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 46 amino acid(s) of the POT1 protein. This variant is present in population databases (rs771968149, gnomAD 0.006%). This premature translational stop signal has been observed in individual(s) with thyroid cancer (PMID: 29625052). ClinVar contains an entry for this variant (Variation ID: 541882). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. This variant disrupts the C-terminus of the POT1 protein. Other variant(s) that disrupt this region (p.Asp617Glufs*9) have been observed in individuals with POT1-related conditions (PMID: 25482530). This suggests that this may be a clinically significant region of the protein. 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. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 03, 2023

The c.1765_1766delAT variant, located in coding exon 14 of the POT1 gene, results from a deletion of two nucleotides at nucleotide positions 1765 to 1766, causing a translational frameshift with a predicted alternate stop codon (p.M589Vfs*9). This alteration occurs at the 3' terminus of thePOT1 gene, is not expected to trigger nonsense-mediated mRNAdecay, and only impacts the last 46 amino acids of the protein. The exact functional effect of this alteration is unknown. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

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: rs771968149; hg19: chr7-124465331;