rs923853643

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_025099.6(CTC1):c.8C>T(p.Ala3Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000118 in 1,443,500 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 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. A3G) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000068 ( 0 hom., cov: 30)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

CTC1
NM_025099.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: -0.512

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 links:

PFAS (HGNC:8863): (phosphoribosylformylglycinamidine synthase) Purines are necessary for many cellular processes, including DNA replication, transcription, and energy metabolism. Ten enzymatic steps are required to synthesize inosine monophosphate (IMP) in the de novo pathway of purine biosynthesis. The enzyme encoded by this gene catalyzes the fourth step of IMP biosynthesis. [provided by RefSeq, Jul 2008]

PFAS links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

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 (MetaRNN=0.061615974).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CTC1	NM_025099.6 linkuse as main transcript	c.8C>T	p.Ala3Val	missense_variant	1/23	ENST00000651323.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CTC1	ENST00000651323.1 linkuse as main transcript	c.8C>T	p.Ala3Val	missense_variant	1/23		NM_025099.6	P1	Q2NKJ3-1

Frequencies

GnomAD3 genomes

AF:

0.00000682

AC:

AN:

146526

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000151

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.0000123

AC:

AN:

1296974

Hom.:

Cov.:

AF XY:

0.0000187

AC XY:

AN XY:

643158

show subpopulations

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:

0.0000139

Gnomad4 OTH exome

AF:

0.0000404

GnomAD4 genome

AF:

0.00000682

AC:

AN:

146526

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

71332

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000151

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Dyskeratosis congenita

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Feb 08, 2018	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. 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 valine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with CTC1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces alanine with valine at codon 3 of the CTC1 protein (p.Ala3Val). The alanine residue is weakly conserved and there is a small physicochemical difference between alanine and valine. -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	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. -

Cerebroretinal microangiopathy with calcifications and cysts 1

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Jul 15, 2021

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Knight Diagnostic Laboratories, Oregon Health and Sciences University

Mar 22, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Benign

-0.067

BayesDel_noAF

Benign

-0.33

Cadd

Benign

3.4

Dann

Benign

0.97

DEOGEN2

Benign

0.015

Eigen

Benign

-1.5

Eigen_PC

Benign

-1.6

FATHMM_MKL

Benign

0.026

LIST_S2

Benign

0.40

M_CAP

Benign

0.078

MetaRNN

Benign

0.062

MetaSVM

Benign

-0.79

MutationAssessor

Benign

1.3

MutationTaster

Benign

1.0

PrimateAI

Benign

0.41

PROVEAN

Benign

-0.67

REVEL

Benign

0.11

Sift

Benign

0.18

Sift4G

Benign

0.50

Polyphen

0.0090

Vest4

0.23

MutPred

0.40

Loss of catalytic residue at M1 (P = 0.0222);

MVP

0.085

MPC

0.12

ClinPred

0.083

GERP RS

-1.7

Varity_R

0.027

gMVP

0.48

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over