rs138725914

Variant names:

• chr17-8237504-A-G
• rs138725914
• NM_025099.6:c.663T>C

Variant summary

Our verdict is Benign. Variant got -14 ACMG points: 0P and 14B. BP4_Strong BP6 BP7 BS1 BS2

The NM_025099.6(CTC1):​c.663T>C​(p.Gly221Gly) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000815 in 1,613,566 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.0011 (1 hom., cov: 29)
  • Exomes 𝑓: 0.00078 (4 hom.)
• Consequence: CTC1 NM_025099.6 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:4
• Conservation: PhyloP100: -0.392

Genes affected

CTC1 (HGNC:26169): (CST telomere replication complex component 1) This gene encodes a component of the CST complex. This complex plays an essential role in protecting telomeres from degradation. This protein also forms a heterodimer with the CST complex subunit STN1 to form the enzyme alpha accessory factor. This enzyme regulates DNA replication. Mutations in this gene are the cause of cerebroretinal microangiopathy with calcifications and cysts. Alternate splicing results in both coding and non-coding variants. [provided by RefSeq, Mar 2012]

ACMG classification

Verdict is Benign. Variant got -14 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.82).
• BP6: Variant 17-8237504-A-G is Benign according to our data. Variant chr17-8237504-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 326083.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Benign=1, Uncertain_significance=1}.
• BP7: Synonymous conserved (PhyloP=-0.392 with no splicing effect.
• BS1: Variant frequency is greater than expected in population eas. gnomad4_exome allele frequency = 0.000783 (1144/1461858) while in subpopulation EAS AF= 0.0108 (427/39698). AF 95% confidence interval is 0.00991. There are 4 homozygotes in gnomad4_exome. There are 540 alleles in male gnomad4_exome subpopulation. Median coverage is 31. This position pass quality control queck.
• BS2: High Homozygotes in GnomAdExome4 at 4 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CTC1	NM_025099.6	c.663T>C	p.Gly221Gly	synonymous_variant	Exon 5 of 23	ENST00000651323.1	NP_079375.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CTC1	ENST00000651323.1	c.663T>C	p.Gly221Gly	synonymous_variant	Exon 5 of 23		NM_025099.6	ENSP00000498499.1

Frequencies

GnomAD3 genomes AF: 0.00113 AC: 172 AN: 151592 Hom.: 1 Cov.: 29

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00542

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0120

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000221

Gnomad OTH AF: 0.000958

GnomAD3 exomes AF: 0.00133 AC: 331 AN: 249502 Hom.: 0 AF XY: 0.00113 AC XY: 153 AN XY: 135366

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00239

Gnomad SAS exome AF: 0.000163

Gnomad FIN exome AF: 0.0112

Gnomad NFE exome AF: 0.000256

Gnomad OTH exome AF: 0.00198

GnomAD4 exome AF: 0.000783 AC: 1144 AN: 1461858 Hom.: 4 Cov.: 31 AF XY: 0.000743 AC XY: 540 AN XY: 727218

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0108

Gnomad4 SAS exome AF: 0.000139

Gnomad4 FIN exome AF: 0.0104

Gnomad4 NFE exome AF: 0.0000845

Gnomad4 OTH exome AF: 0.000894

GnomAD4 genome AF: 0.00113 AC: 171 AN: 151708 Hom.: 1 Cov.: 29 AF XY: 0.00148 AC XY: 110 AN XY: 74134

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00543

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0120

Gnomad4 NFE AF: 0.000221

Gnomad4 OTH AF: 0.000474

Alfa AF: 0.000430 Hom.: 0

Bravo AF: 0.000151

Asia WGS AF: 0.00404 AC: 14 AN: 3478

EpiCase AF: 0.000164

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:4

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Dyskeratosis congenita Uncertain:1 Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Jan 25, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cerebroretinal microangiopathy with calcifications and cysts 1 Benign:1

Jul 15, 2021

Genome-Nilou Lab

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

CTC1-related disorder Benign:1

Sep 03, 2019

PreventionGenetics, part of Exact Sciences

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant is classified as benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

not provided Benign:1

Dec 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

CTC1: BP4, BP7, BS1 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.82
CADD	Benign	7.9
DANN	Benign	0.81

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs138725914; hg19: chr17-8140822;