rs773758089

Variant names:

• chr5-1294336-C-T
• rs773758089
• NM_198253.3:c.550G>A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 4P and 4B. PM1 PM2 BP4_Strong

The NM_198253.3(TERT):​c.550G>A​(p.Ala184Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000259 in 1,427,070 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.000026 (0 hom.)
• Consequence: TERT NM_198253.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: -0.687

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 Uncertain_significance. Variant got 0 ACMG points.

• PM1: In a region_of_interest RNA-interacting domain 1 (size 229) in uniprot entity TERT_HUMAN there are 10 pathogenic changes around while only 3 benign (77%) in NM_198253.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.059318423).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TERT	NM_198253.3	c.550G>A	p.Ala184Thr	missense_variant	Exon 2 of 16	ENST00000310581.10	NP_937983.2
TERT	NM_001193376.3	c.550G>A	p.Ala184Thr	missense_variant	Exon 2 of 15		NP_001180305.1
TERT	NR_149162.3	n.629G>A		non_coding_transcript_exon_variant	Exon 2 of 13
TERT	NR_149163.3	n.629G>A		non_coding_transcript_exon_variant	Exon 2 of 13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TERT	ENST00000310581.10	c.550G>A	p.Ala184Thr	missense_variant	Exon 2 of 16	1	NM_198253.3	ENSP00000309572.5
TERT	ENST00000334602.10	c.550G>A	p.Ala184Thr	missense_variant	Exon 2 of 15	1		ENSP00000334346.6
TERT	ENST00000460137.6	n.550G>A		non_coding_transcript_exon_variant	Exon 2 of 13	1		ENSP00000425003.1
TERT	ENST00000656021.1	n.550G>A		non_coding_transcript_exon_variant	Exon 2 of 17			ENSP00000499759.1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.0000165 AC: 3 AN: 182336 Hom.: 0 AF XY: 0.0000294 AC XY: 3 AN XY: 102026

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

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: 0.0000384

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000259 AC: 37 AN: 1427070 Hom.: 0 Cov.: 35 AF XY: 0.0000240 AC XY: 17 AN XY: 708914

Gnomad4 AFR exome AF: 0.0000303

Gnomad4 AMR exome AF: 0.00

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: 0.0000327

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

Bravo AF: 0.0000151

ExAC AF: 0.0000347 AC: 4

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Nov 03, 2021

Institute for Clinical Genetics, University Hospital TU Dresden, University Hospital TU Dresden

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 26, 2022

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

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

Apr 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 184 of the TERT protein (p.Ala184Thr). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with TERT-related conditions. ClinVar contains an entry for this variant (Variation ID: 471895). 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 with a negative predictive value of 80%. 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. -

Dyskeratosis congenita Benign:1

Dec 19, 2024

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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	0.074
BayesDel_addAF	Benign	-0.12	T
BayesDel_noAF	Benign	-0.41
CADD	Benign	0.26
DANN	Benign	0.75
DEOGEN2	Benign	0.35	T;.
Eigen	Benign	-1.6
Eigen_PC	Benign	-1.7
FATHMM_MKL	Benign	0.055	N
LIST_S2	Benign	0.52	T;T
M_CAP	Uncertain	0.22	D
MetaRNN	Benign	0.059	T;T
MetaSVM	Uncertain	-0.060	T
MutationAssessor	Benign	0.73	N;N
PrimateAI	Uncertain	0.59	T
PROVEAN	Benign	-0.37	N;N
REVEL	Benign	0.16
Sift	Benign	0.39	T;T
Sift4G	Benign	0.37	T;T
Polyphen		0.0010	B;B
Vest4		0.060
MutPred		0.13		Gain of glycosylation at A184 (P = 0.0012);Gain of glycosylation at A184 (P = 0.0012);
MVP		0.58
MPC		1.0
ClinPred		0.052	T
GERP RS		-4.1
Varity_R		0.032
gMVP		0.66

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: rs773758089; hg19: chr5-1294451; COSMIC: COSV57200309; COSMIC: COSV57200309;