17-8230395-AG-AGG

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong

The NM_025099.6(CTC1):c.2831dupC(p.His945SerfsTer56) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000805 in 1,614,008 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

CTC1
NM_025099.6 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3

Conservation

PhyloP100: 0.393

Publications

5 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: Pathogenic. The variant received 16 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PP5

Variant 17-8230395-A-AG is Pathogenic according to our data. Variant chr17-8230395-A-AG is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 840769.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.2831dupC	p.His945SerfsTer56	frameshift	Exon 17 of 23	NP_079375.3
CTC1	NM_001411067.1		c.2831dupC	p.His945SerfsTer56	frameshift	Exon 17 of 21	NP_001397996.1
CTC1	NR_046431.2		n.2746dupC		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.2831dupC	p.His945SerfsTer56	frameshift	Exon 17 of 23	ENSP00000498499.1
CTC1	ENST00000581729.2	TSL:3	c.2831dupC	p.His945SerfsTer56	frameshift	Exon 17 of 21	ENSP00000462720.2
CTC1	ENST00000580299.2	TSL:5	c.2831dupC	p.His945SerfsTer56	frameshift	Exon 17 of 21	ENSP00000462607.2

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152136

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000120

AC:

AN:

249486

AF XY:

0.0000148

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.00000752

AC:

AN:

1461872

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

727240

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00000809

AC:

AN:

1112006

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.484

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:

0.0000131

AC:

AN:

152136

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74310

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41432

American (AMR)

AF:

0.00

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68020

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.600

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:

0.00

Hom.:

Bravo

AF:

0.0000113

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cerebroretinal microangiopathy with calcifications and cysts 1

Pathogenic:1

Apr 17, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: CTC1 c.2831dupC (p.His945SerfsX56) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant allele was found at a frequency of 1.2e-05 in 249486 control chromosomes (gnomAD). c.2831dupC has been reported in the compound heterozygous state in the literature in an individual affected with Coats plus (Anderson_2012). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and both classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic.

not provided

Pathogenic:1

Nov 30, 2020

Genetic Services Laboratory, University of Chicago

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

DNA sequence analysis of the CTC1 gene demonstrated a single base pair duplication in exon 17, c.2831dup. This pathogenic sequence change results in an amino acid frameshift and creates a premature stop codon 55 amino acids downstream of the change, p.His945Serfs*56. This sequence change is predicted to result in an abnormal transcript, which may be degraded, or may lead to the production of a truncated CTC1 protein with potentially abnormal function. This sequence change has previously been described in a patient with Coats Plus disease in a compound heterozygous state with another splice site variant (PMID: 22267198). This sequence change has been described in the gnomAD database with a low population frequency of 0.0014% (dbSNP rs779650334); it has been observed in 4 heterozygous individuals.

Dyskeratosis congenita

Pathogenic:1

Dec 25, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.His945Serfs*56) in the CTC1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CTC1 are known to be pathogenic (PMID: 22267198, 22387016). This variant is present in population databases (rs779650334, gnomAD 0.003%). This premature translational stop signal has been observed in individual(s) with Coats plus syndrome (PMID: 22267198). ClinVar contains an entry for this variant (Variation ID: 840769). For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

PhyloP100

0.39

Mutation Taster

=13/187

disease causing (ClinVar)

(source)

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

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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