rs756967332

Positions:

• chr3-169764870-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NR_001566.1(TERC):​n.191C>T variant causes a non coding transcript exon change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000495 in 606,462 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000049 (0 hom.)
• Consequence: TERC NR_001566.1 non_coding_transcript_exon
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 0.768

Genes affected

Telomerase-vert (HGNC:):

TERC (HGNC:11727): (telomerase RNA component) 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, and an RNA component, encoded by this gene, that 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. Mutations in this gene cause autosomal dominant dyskeratosis congenita, and may also be associated with some cases of aplastic anemia. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.51).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TERC	NR_001566.1	n.191C>T		non_coding_transcript_exon_variant	1/1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
Telomerase-vert	ENST00000363312.1	n.178C>T		non_coding_transcript_exon_variant	1/1
TERC	ENST00000602385.1	n.191C>T		non_coding_transcript_exon_variant	1/1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000463 AC: 1 AN: 215772 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 119922

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: 0.0000101

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000495 AC: 3 AN: 606462 Hom.: 0 Cov.: 0 AF XY: 0.00000302 AC XY: 1 AN XY: 331210

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: 0.00000865

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Genetic Services Laboratory, University of Chicago

Dec 12, 2022

DNA sequence analysis of the TERC gene demonstrated a sequence change in exon 1, n.191C>T. This change does not appear to have been previously described in individuals with TERC-related disorders. This sequence change has been described in the gnomAD database in one individual which corresponds to a population frequency of 0.00046% (dbSNP rs756967332). This sequence change affects a poorly conserved nucleotide located in a domain that is not known to be functional. The functional significance of this sequence change is not known at present and its contribution to this individual's disease phenotype cannot definitively be determined. -

Dyskeratosis congenita, autosomal dominant 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 04, 2023

This variant occurs in the TERC gene, which encodes an RNA molecule that does not result in a protein product. 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 TERC-related conditions. ClinVar contains an entry for this variant (Variation ID: 465763). This variant is located within the template/pseudoknot domain of the TERC RNA component, which is required for RNA or RNP stability (PMID: 15082312, 21844345). This variant is located in a region of TERC in which a significant number of disease causing variants have been reported (PMID: 15082312, 21844345, 21931702). These observations suggest that this may be a clinically significant region. 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
BayesDel_noAF	Benign	-0.51
CADD	Benign	11
DANN	Benign	0.90
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.2

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs756967332; hg19: chr3-169482658;