chr5-1293360-G-A

Position:

• chr5-1293360-G-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP6

The NM_198253.3(TERT):​c.1526C>T​(p.Thr509Met) 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. T509T) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 34)
• Consequence: TERT NM_198253.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 0.955

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]

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.081278205).
• BP6: Variant 5-1293360-G-A is Benign according to our data. Variant chr5-1293360-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 539185.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TERT	NM_198253.3	c.1526C>T	p.Thr509Met	missense_variant	2/16	ENST00000310581.10
TERT	NM_001193376.3	c.1526C>T	p.Thr509Met	missense_variant	2/15
TERT	NR_149162.3	n.1605C>T		non_coding_transcript_exon_variant	2/13
TERT	NR_149163.3	n.1605C>T		non_coding_transcript_exon_variant	2/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TERT	ENST00000310581.10	c.1526C>T	p.Thr509Met	missense_variant	2/16	1	NM_198253.3	P2
TERT	ENST00000334602.10	c.1526C>T	p.Thr509Met	missense_variant	2/15	1		A2
TERT	ENST00000460137.6	c.1526C>T	p.Thr509Met	missense_variant, NMD_transcript_variant	2/13	1
TERT	ENST00000656021.1	c.1526C>T	p.Thr509Met	missense_variant, NMD_transcript_variant	2/17

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 34

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

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

Aug 22, 2022

This variant is not present in population databases (gnomAD no frequency). This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 509 of the TERT protein (p.Thr509Met). This variant has not been reported in the literature in individuals affected with TERT-related conditions. 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 not expected to disrupt TERT protein function. ClinVar contains an entry for this variant (Variation ID: 539185). -

Dyskeratosis congenita Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 30, 2022

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.088
BayesDel_addAF	Benign	-0.11	T
BayesDel_noAF	Benign	-0.40
CADD	Benign	6.4
DANN	Benign	0.077
DEOGEN2	Benign	0.34	T;.
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.31	N
LIST_S2	Benign	0.84	T;T
M_CAP	Uncertain	0.20	D
MetaRNN	Benign	0.081	T;T
MetaSVM	Benign	-0.63	T
MutationAssessor	Benign	-0.32	N;N
MutationTaster	Benign	1.0	N;N;N;N
PrimateAI	Benign	0.35	T
PROVEAN	Benign	1.0	N;N
REVEL	Benign	0.19
Sift	Benign	1.0	T;T
Sift4G	Benign	1.0	T;T
Polyphen		0.51	P;B
Vest4		0.077
MutPred		0.32		Gain of catalytic residue at T509 (P = 0.0231);Gain of catalytic residue at T509 (P = 0.0231);
MVP		0.32
MPC		1.1
ClinPred		0.095	T
GERP RS		-2.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.036
gMVP		0.49

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: rs1554042799; hg19: chr5-1293475; COSMIC: COSV57248775; COSMIC: COSV57248775;