17-8225938-C-T

Variant names:

• chr17-8225938-C-T
• rs868833357
• NM_025099.6:c.*2242G>A

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_025099.6(CTC1):​c.*2242G>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00073 in 152,068 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00073 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: CTC1 NM_025099.6 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.558
• Publications: 0 publications found

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

ENSG00000305852 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.86).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CTC1	NM_025099.6	c.*2242G>A		3_prime_UTR_variant	Exon 23 of 23	ENST00000651323.1	NP_079375.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CTC1	ENST00000651323.1	c.*2242G>A		3_prime_UTR_variant	Exon 23 of 23		NM_025099.6	ENSP00000498499.1
ENSG00000305852	ENST00000813477.1	n.540C>T		non_coding_transcript_exon_variant	Exon 2 of 2
ENSG00000305852	ENST00000813476.1	n.*105C>T		downstream_gene_variant

Frequencies

GnomAD3 genomes AF: 0.000737 AC: 112 AN: 151950 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00171

Gnomad ASJ AF: 0.00289

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000829

Gnomad FIN AF: 0.0000946

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.000985

Gnomad OTH AF: 0.000959

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 16 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 12

African (AFR) AC: 0 AN: 0

American (AMR) AC: 0 AN: 0

Ashkenazi Jewish (ASJ) AC: 0 AN: 0

East Asian (EAS) AC: 0 AN: 0

South Asian (SAS) AC: 0 AN: 0

European-Finnish (FIN) AC: 0 AN: 0

Middle Eastern (MID) AC: 0 AN: 0

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 16

Other (OTH) AC: 0 AN: 0

GnomAD4 genome AF: 0.000730 AC: 111 AN: 152068 Hom.: 0 Cov.: 32 AF XY: 0.000686 AC XY: 51 AN XY: 74358

African (AFR) AF: 0.0000241 AC: 1 AN: 41472

American (AMR) AF: 0.00170 AC: 26 AN: 15252

Ashkenazi Jewish (ASJ) AF: 0.00289 AC: 10 AN: 3464

East Asian (EAS) AF: 0.00 AC: 0 AN: 5180

South Asian (SAS) AF: 0.000830 AC: 4 AN: 4822

European-Finnish (FIN) AF: 0.0000946 AC: 1 AN: 10568

Middle Eastern (MID) AF: 0.00340 AC: 1 AN: 294

European-Non Finnish (NFE) AF: 0.000971 AC: 66 AN: 67996

Other (OTH) AF: 0.000949 AC: 2 AN: 2108

Alfa AF: 0.000106 Hom.: 0

Bravo AF: 0.000638

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Dyskeratosis congenita Uncertain:1

Jan 13, 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.86
CADD	Benign	0.99
DANN	Benign	0.69
PhyloP100		0.56

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

Other links and lift over

dbSNP: rs868833357; hg19: chr17-8129256;