rs727503468

Variant names:

• chr5-1278702-C-T
• rs727503468
• NM_198253.3:c.2225G>A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_198253.3(TERT):​c.2225G>A​(p.Arg742His) 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 1,461,810 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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 P:1 U:5
• Conservation: PhyloP100: 1.94

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 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.858

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TERT	NM_198253.3	c.2225G>A	p.Arg742His	missense_variant	Exon 6 of 16	ENST00000310581.10	NP_937983.2
TERT	NM_001193376.3	c.2225G>A	p.Arg742His	missense_variant	Exon 6 of 15		NP_001180305.1
TERT	NR_149162.3	n.2304G>A		non_coding_transcript_exon_variant	Exon 6 of 13
TERT	NR_149163.3	n.2268G>A		non_coding_transcript_exon_variant	Exon 6 of 13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TERT	ENST00000310581.10	c.2225G>A	p.Arg742His	missense_variant	Exon 6 of 16	1	NM_198253.3	ENSP00000309572.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461810 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727206

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: 0.00

Gnomad4 FIN exome AF: 0.0000187

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Jun 30, 2020

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 28099038, 25393420, 30995915) -

Nov 24, 2019

Mayo Clinic Laboratories, Mayo Clinic

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Pulmonary fibrosis Pathogenic:1

Jun 09, 2022

Garcia Pulmonary Genetics Research Laboratory, Columbia University Irving Medical Center

Significance: Likely risk allele

Review Status: no assertion criteria provided

Collection Method: research

Leukocyte telomere length (by qPCR) less than 10th percentile age-adjusted -

not specified Uncertain:1

Aug 19, 2014

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Arg742His variant in TERT has not been previously identified in individuals with pulmonary disease or in large population studies. Computation tools (bioche mical amino acid properties, conservation, AlignGVGD, PolyPhen-2, and SIFT) do n ot provide strong support for or against an impact to the protein. In summary, a dditional information is needed to fully assess the clinical significance of the Arg742His variant. -

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

Jul 13, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 742 of the TERT protein (p.Arg742His). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with pulmonary fibrosis and inherited bone marrow failure syndrome (PMID: 28099038, 30995915, 33718801). ClinVar contains an entry for this variant (Variation ID: 165378). 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. 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 Uncertain:1

Oct 21, 2016

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R742H variant (also known as c.2225G>A), located in coding exon 6 of the TERT gene, results from a G to A substitution at nucleotide position 2225. The arginine at codon 742 is replaced by histidine, an amino acid with highly similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6503 samples (13006 alleles) with coverage at this position. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. 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	Uncertain	0.44
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.15
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.68	D;.
Eigen	Uncertain	0.22
Eigen_PC	Benign	0.11
FATHMM_MKL	Benign	0.47	N
LIST_S2	Uncertain	0.88	D;D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.86	D;D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Benign	2.0	M;M
PrimateAI	Benign	0.47	T
PROVEAN	Uncertain	-3.1	D;D
REVEL	Pathogenic	0.71
Sift	Uncertain	0.023	D;D
Sift4G	Uncertain	0.042	D;D
Polyphen		0.99	D;D
Vest4		0.50
MutPred		0.61		Loss of MoRF binding (P = 0.014);Loss of MoRF binding (P = 0.014);
MVP		0.95
MPC		1.7
ClinPred		0.97	D
GERP RS		3.7
Varity_R		0.32
gMVP		0.92

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

LitVar

Other links and lift over

dbSNP: rs727503468; hg19: chr5-1278817; COSMIC: COSV57213437;