5-1294332-C-T

Variant names:

• chr5-1294332-C-T
• rs749187042
• NM_198253.3:c.554G>A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_198253.3(TERT):​c.554G>A​(p.Arg185Gln) 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. 13/21 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: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TERT NM_198253.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.12

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 2 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=0.13078392).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TERT	NM_198253.3	c.554G>A	p.Arg185Gln	missense_variant	Exon 2 of 16	ENST00000310581.10	NP_937983.2
TERT	NM_001193376.3	c.554G>A	p.Arg185Gln	missense_variant	Exon 2 of 15		NP_001180305.1
TERT	NR_149162.3	n.633G>A		non_coding_transcript_exon_variant	Exon 2 of 13
TERT	NR_149163.3	n.633G>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.554G>A	p.Arg185Gln	missense_variant	Exon 2 of 16	1	NM_198253.3	ENSP00000309572.5
TERT	ENST00000334602.10	c.554G>A	p.Arg185Gln	missense_variant	Exon 2 of 15	1		ENSP00000334346.6
TERT	ENST00000460137.6	n.554G>A		non_coding_transcript_exon_variant	Exon 2 of 13	1		ENSP00000425003.1
TERT	ENST00000656021.1	n.554G>A		non_coding_transcript_exon_variant	Exon 2 of 17			ENSP00000499759.1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1429120 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 710052

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ExAC AF: 0.00000866 AC: 1

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

Aug 28, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine with glutamine at codon 185 of the TERT protein (p.Arg185Gln). The arginine residue is weakly conserved and there is a small physicochemical difference between arginine and glutamine. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the ExAC database. This variant has not been reported in the literature in individuals affected with TERT-related conditions. 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 glutamine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.091
BayesDel_addAF	Benign	-0.059	T
BayesDel_noAF	Benign	-0.32
CADD	Benign	3.3
DANN	Uncertain	0.99
DEOGEN2	Benign	0.38	T;.
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.3
FATHMM_MKL	Benign	0.028	N
LIST_S2	Benign	0.63	T;T
M_CAP	Pathogenic	0.42	D
MetaRNN	Benign	0.13	T;T
MetaSVM	Uncertain	0.066	D
MutationAssessor	Benign	0.81	L;L
PrimateAI	Uncertain	0.50	T
PROVEAN	Benign	-0.92	N;N
REVEL	Benign	0.18
Sift	Benign	0.39	T;T
Sift4G	Benign	0.58	T;T
Polyphen		0.35	B;P
Vest4		0.066
MutPred		0.21		Loss of helix (P = 0.028);Loss of helix (P = 0.028);
MVP		0.70
MPC		1.2
ClinPred		0.16	T
GERP RS		-2.5
Varity_R		0.027
gMVP		0.67

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: rs749187042; hg19: chr5-1294447;