5-1253741-G-T

Position:

• chr5-1253741-G-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.3386C>A​(p.Thr1129Asn) 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. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: TERT NM_198253.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.881

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]

(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=0.32896122).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TERT	NM_198253.3	c.3386C>A	p.Thr1129Asn	missense_variant	16/16	ENST00000310581.10	NP_937983.2
TERT	NM_001193376.3	c.3197C>A	p.Thr1066Asn	missense_variant	15/15		NP_001180305.1
TERT	NR_149162.3	n.3094C>A		non_coding_transcript_exon_variant	13/13
TERT	NR_149163.3	n.3058C>A		non_coding_transcript_exon_variant	13/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TERT	ENST00000310581.10	c.3386C>A	p.Thr1129Asn	missense_variant	16/16	1	NM_198253.3	ENSP00000309572	P2
	ENST00000666708.1	n.289-933G>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

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

Dec 12, 2020

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 threonine with asparagine at codon 1129 of the TERT protein (p.Thr1129Asn). The threonine residue is moderately conserved and there is a small physicochemical difference between threonine and asparagine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.097
BayesDel_addAF	Uncertain	0.025	T
BayesDel_noAF	Benign	-0.20
CADD	Benign	18
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.43	T;.
Eigen	Benign	-0.20
Eigen_PC	Benign	-0.27
FATHMM_MKL	Benign	0.57	D
LIST_S2	Benign	0.78	T;T
M_CAP	Pathogenic	0.77	D
MetaRNN	Benign	0.33	T;T
MetaSVM	Uncertain	0.51	D
MutationAssessor	Uncertain	2.6	M;.
MutationTaster	Benign	0.55	D;D;N
PrimateAI	Benign	0.47	T
PROVEAN	Benign	-1.7	N;N
REVEL	Uncertain	0.40
Sift	Uncertain	0.018	D;D
Sift4G	Uncertain	0.0090	D;D
Polyphen		0.99	D;B
Vest4		0.20
MutPred		0.15		Loss of phosphorylation at T1129 (P = 0.0271);.;
MVP		0.92
MPC		1.7
ClinPred		0.48	T
GERP RS		0.97
Varity_R		0.10
gMVP		0.45

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: rs775095158; hg19: chr5-1253856;