Genetic Variant NM_025099.6:c.228C>A (chr17-8238599-G-T) – ACMG Classification: Uncertain_significance (0 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_025099.6(CTC1):c.228C>A(p.His76Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,459,892 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 (★).

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

CTC1
NM_025099.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -0.683

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:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.10865992).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CTC1	NM_025099.6 link	c.228C>A	p.His76Gln	missense_variant	Exon 3 of 23	ENST00000651323.1	NP_079375.3	Q2NKJ3-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CTC1	ENST00000651323.1 link	c.228C>A	p.His76Gln	missense_variant	Exon 3 of 23		NM_025099.6	ENSP00000498499.1		Q2NKJ3-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1459892

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726178

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:

9.00e-7

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Dyskeratosis congenita

Uncertain:1

Jun 24, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0". The glutamine 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 conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces histidine with glutamine at codon 76 of the CTC1 protein (p.His76Gln). The histidine residue is moderately conserved and there is a small physicochemical difference between histidine and glutamine. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.15

BayesDel_addAF

Benign

-0.080

BayesDel_noAF

Benign

-0.35

CADD

Benign

9.7

DANN

Benign

0.97

DEOGEN2

Benign

0.40

Eigen

Benign

-0.56

Eigen_PC

Benign

-0.50

FATHMM_MKL

Benign

0.28

LIST_S2

Benign

0.50

M_CAP

Benign

0.025

MetaRNN

Benign

0.11

MetaSVM

Benign

-0.83

MutationAssessor

Benign

1.5

PrimateAI

Benign

0.33

PROVEAN

Benign

-2.0

REVEL

Benign

0.094

Sift

Benign

0.40

Sift4G

Uncertain

0.020

Polyphen

0.057

Vest4

0.22

MutPred

0.39

Gain of catalytic residue at H76 (P = 0.0564);

MVP

0.46

MPC

0.34

ClinPred

0.33

GERP RS

-0.077

Varity_R

0.047

gMVP

0.26

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over