rs756628621

Positions:

• chr5-1253775-C-A
• chr5-1253775-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_198253.3(TERT):​c.3352G>T​(p.Ala1118Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,459,822 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TERT NM_198253.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.17

Genes affected

TERT (HGNC:11730): (telomerase reverse transcriptase) Telomerase is a ribonucleoprotein polymerase that maintains telomere ends by addition of the telomere repeat TTAGGG. The enzyme consists of a protein component with reverse transcriptase activity, encoded by this gene, and an RNA component which serves as a template for the telomere repeat. Telomerase expression plays a role in cellular senescence, as it is normally repressed in postnatal somatic cells resulting in progressive shortening of telomeres. Deregulation of telomerase expression in somatic cells may be involved in oncogenesis. Studies in mouse suggest that telomerase also participates in chromosomal repair, since de novo synthesis of telomere repeats may occur at double-stranded breaks. Alternatively spliced variants encoding different isoforms of telomerase reverse transcriptase have been identified; the full-length sequence of some variants has not been determined. Alternative splicing at this locus is thought to be one mechanism of regulation of telomerase activity. [provided by RefSeq, Jul 2008]

TERT (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a region_of_interest CTE (size 196) in uniprot entity TERT_HUMAN there are 17 pathogenic changes around while only 4 benign (81%) in NM_198253.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.35345274).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TERT	NM_198253.3	c.3352G>T	p.Ala1118Ser	missense_variant	16/16	ENST00000310581.10	NP_937983.2
TERT	NM_001193376.3	c.3163G>T	p.Ala1055Ser	missense_variant	15/15		NP_001180305.1
TERT	NR_149162.3	n.3060G>T		non_coding_transcript_exon_variant	13/13
TERT	NR_149163.3	n.3024G>T		non_coding_transcript_exon_variant	13/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TERT	ENST00000310581.10	c.3352G>T	p.Ala1118Ser	missense_variant	16/16	1	NM_198253.3	ENSP00000309572.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1459822 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726118

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: 0.0000233

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Idiopathic Pulmonary Fibrosis;C3151443:Dyskeratosis congenita, autosomal dominant 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 09, 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. 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 expected to disrupt TERT protein function. This variant has not been reported in the literature in individuals with TERT-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces alanine with serine at codon 1118 of the TERT protein (p.Ala1118Ser). The alanine residue is moderately conserved and there is a moderate physicochemical difference between alanine and serine. -

Dyskeratosis congenita Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 11, 2022

The p.A1118S variant (also known as c.3352G>T), located in coding exon 16 of the TERT gene, results from a G to T substitution at nucleotide position 3352. The alanine at codon 1118 is replaced by serine, an amino acid with similar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. 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	0.14
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	-0.080
CADD	Benign	18
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.61	D;.
Eigen	Benign	-0.30
Eigen_PC	Benign	-0.54
FATHMM_MKL	Benign	0.075	N
LIST_S2	Benign	0.74	T;T
M_CAP	Pathogenic	0.74	D
MetaRNN	Benign	0.35	T;T
MetaSVM	Uncertain	0.62	D
MutationAssessor	Uncertain	2.7	M;.
PrimateAI	Benign	0.38	T
PROVEAN	Benign	-1.6	N;N
REVEL	Uncertain	0.34
Sift	Uncertain	0.014	D;D
Sift4G	Uncertain	0.016	D;D
Polyphen		0.99	D;D
Vest4		0.19
MutPred		0.26		Gain of glycosylation at A1118 (P = 0.0044);.;
MVP		0.72
MPC		1.8
ClinPred		0.92	D
GERP RS		2.9
Varity_R		0.37
gMVP		0.56

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr5-1253890;