17-8230457-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_025099.6(CTC1):c.2770G>A(p.Ala924Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000682 in 1,613,526 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 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. A924D) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

CTC1
NM_025099.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: -0.471

Publications

0 publications found

Variant links:

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]

CTC1 Gene-Disease associations (from GenCC):

cerebroretinal microangiopathy with calcifications and cysts 1
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia, Ambry Genetics, G2P
dyskeratosis congenita
Inheritance: AR, AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, Orphanet
Coats plus syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

CTC1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.083884746).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_025099.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CTC1	NM_025099.6	MANE Select	c.2770G>A	p.Ala924Thr	missense	Exon 17 of 23	NP_079375.3
CTC1	NM_001411067.1		c.2770G>A	p.Ala924Thr	missense	Exon 17 of 21	NP_001397996.1
CTC1	NR_046431.2		n.2685G>A		non_coding_transcript_exon	Exon 17 of 22

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CTC1	ENST00000651323.1	MANE Select	c.2770G>A	p.Ala924Thr	missense	Exon 17 of 23	ENSP00000498499.1
CTC1	ENST00000581729.2	TSL:3	c.2770G>A	p.Ala924Thr	missense	Exon 17 of 21	ENSP00000462720.2
CTC1	ENST00000580299.2	TSL:5	c.2770G>A	p.Ala924Thr	missense	Exon 17 of 21	ENSP00000462607.2

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000145

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461354

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726952

show subpopulations

African (AFR)

AF:

0.000120

AC:

AN:

33460

American (AMR)

AF:

0.00

AC:

AN:

44676

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26086

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86188

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53408

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111704

Other (OTH)

AF:

0.00

AC:

AN:

60364

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.455

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74352

show subpopulations

African (AFR)

AF:

0.000145

AC:

AN:

41436

American (AMR)

AF:

0.00

AC:

AN:

15276

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000329

Hom.:

Bravo

AF:

0.0000227

ESP6500AA

AF:

0.000258

AC:

ESP6500EA

AF:

0.00

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

May 31, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.2770G>A (p.A924T) alteration is located in exon 17 (coding exon 17) of the CTC1 gene. This alteration results from a G to A substitution at nucleotide position 2770, causing the alanine (A) at amino acid position 924 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Dyskeratosis congenita

Uncertain:1

Feb 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 924 of the CTC1 protein (p.Ala924Thr). This variant is present in population databases (rs376358881, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with CTC1-related conditions. ClinVar contains an entry for this variant (Variation ID: 566947). 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 not expected to disrupt CTC1 protein function with a negative predictive value of 80%. 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 v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.079

BayesDel_addAF

Benign

-0.19

BayesDel_noAF

Benign

-0.51

CADD

Benign

(source)

DANN

Benign

0.55

DEOGEN2

Benign

0.28

Eigen

Benign

-1.2

Eigen_PC

Benign

-1.2

FATHMM_MKL

Benign

0.039

LIST_S2

Benign

0.55

M_CAP

Benign

0.028

MetaRNN

Benign

0.084

MetaSVM

Benign

-0.88

MutationAssessor

Benign

1.9

PhyloP100

-0.47

PrimateAI

Benign

0.29

PROVEAN

Benign

-1.3

REVEL

Benign

0.055

Sift

Benign

0.40

Sift4G

Benign

0.26

Polyphen

0.035

Vest4

0.10

MVP

0.23

MPC

0.13

ClinPred

0.030

GERP RS

-1.1

PromoterAI

0.0054

Neutral

(source)

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.025

gMVP

0.20

Mutation Taster

=98/2

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.16

Details are displayed if max score is > 0.2

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

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over