chr5-1278706-C-G

Variant names:

• chr5-1278706-C-G
• NM_198253.3:c.2221G>C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_198253.3(TERT):​c.2221G>C​(p.Val741Leu) 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 1,461,808 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V741M) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TERT NM_198253.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.941

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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.30979627).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TERT	NM_198253.3	c.2221G>C	p.Val741Leu	missense_variant	Exon 6 of 16	ENST00000310581.10	NP_937983.2
TERT	NM_001193376.3	c.2221G>C	p.Val741Leu	missense_variant	Exon 6 of 15		NP_001180305.1
TERT	NR_149162.3	n.2300G>C		non_coding_transcript_exon_variant	Exon 6 of 13
TERT	NR_149163.3	n.2264G>C		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.2221G>C	p.Val741Leu	missense_variant	Exon 6 of 16	1	NM_198253.3	ENSP00000309572.5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461808 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727204

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: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

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

Feb 14, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on TERT function (PMID: 34019641). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The leucine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. This missense change has been observed in individual(s) with myelodysplastic syndrome (PMID: 34019641). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 741 of the TERT protein (p.Val741Leu). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.064	T
BayesDel_noAF	Benign	-0.33
CADD	Benign	0.15
DANN	Benign	0.96
DEOGEN2	Benign	0.39	T;.
Eigen	Benign	-0.94
Eigen_PC	Benign	-0.94
FATHMM_MKL	Benign	0.085	N
LIST_S2	Benign	0.74	T;T
M_CAP	Pathogenic	0.67	D
MetaRNN	Benign	0.31	T;T
MetaSVM	Uncertain	0.064	D
MutationAssessor	Benign	0.97	L;L
PrimateAI	Benign	0.33	T
PROVEAN	Benign	-0.61	N;N
REVEL	Benign	0.17
Sift	Uncertain	0.018	D;D
Sift4G	Uncertain	0.017	D;D
Polyphen		0.021	B;B
Vest4		0.094
MutPred		0.43		Gain of catalytic residue at V741 (P = 0.0623);Gain of catalytic residue at V741 (P = 0.0623);
MVP		0.49
MPC		1.0
ClinPred		0.13	T
GERP RS		0.25
Varity_R		0.085
gMVP		0.83

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr5-1278821;