chr17-8231467-T-C

Position:

• chr17-8231467-T-C

Variant summary

Our verdict is Benign. Variant got -10 ACMG points: 0P and 10B. BP4_Strong BP6 BP7 BS2

The NM_025099.6(CTC1):​c.2478A>G​(p.Thr826=) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00082 in 1,603,758 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.0013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00076 (5 hom.)
• Consequence: CTC1 NM_025099.6 splice_region, synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:7
• Conservation: PhyloP100: -1.96

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]

ACMG classification

Verdict is Benign. Variant got -10 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.94).
• BP6: Variant 17-8231467-T-C is Benign according to our data. Variant chr17-8231467-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 241581.We mark this variant Likely_benign, oryginal submissions are: {Benign=2, Likely_benign=3, Uncertain_significance=1}. Variant chr17-8231467-T-C is described in Lovd as [Likely_benign].
• BP7: Synonymous conserved (PhyloP=-1.96 with no splicing effect.
• BS2: High Homozygotes in GnomAdExome4 at 5 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CTC1	NM_025099.6	c.2478A>G	p.Thr826=	splice_region_variant, synonymous_variant	15/23	ENST00000651323.1	NP_079375.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CTC1	ENST00000651323.1	c.2478A>G	p.Thr826=	splice_region_variant, synonymous_variant	15/23		NM_025099.6	ENSP00000498499	P1

Frequencies

GnomAD3 genomes AF: 0.00135 AC: 205 AN: 152178 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00104

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00366

Gnomad ASJ AF: 0.0170

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000559

Gnomad OTH AF: 0.00431

GnomAD3 exomes AF: 0.00135 AC: 328 AN: 243054 Hom.: 1 AF XY: 0.00131 AC XY: 173 AN XY: 131940

Gnomad AFR exome AF: 0.00104

Gnomad AMR exome AF: 0.00211

Gnomad ASJ exome AF: 0.0181

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000453

Gnomad OTH exome AF: 0.00325

GnomAD4 exome AF: 0.000765 AC: 1110 AN: 1451462 Hom.: 5 Cov.: 32 AF XY: 0.000754 AC XY: 544 AN XY: 721116

Gnomad4 AFR exome AF: 0.000875

Gnomad4 AMR exome AF: 0.00186

Gnomad4 ASJ exome AF: 0.0173

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000117

Gnomad4 FIN exome AF: 0.0000188

Gnomad4 NFE exome AF: 0.000362

Gnomad4 OTH exome AF: 0.00232

GnomAD4 genome AF: 0.00135 AC: 205 AN: 152296 Hom.: 0 Cov.: 32 AF XY: 0.00133 AC XY: 99 AN XY: 74474

Gnomad4 AFR AF: 0.00103

Gnomad4 AMR AF: 0.00366

Gnomad4 ASJ AF: 0.0170

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000559

Gnomad4 OTH AF: 0.00427

Alfa AF: 0.00196 Hom.: 0

Bravo AF: 0.00164

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:7

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Benign:3

Likely benign, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Jul 05, 2019	- -
Likely benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

Dyskeratosis congenita Uncertain:1 Benign:1

Benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 31, 2024	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 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 Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago	Jan 18, 2023	This variant has not been reported in the literature but is present in the Genome Aggregation Database (Highest reported MAF 0.2% [72/34082]; https://gnomad.broadinstitute.org/variant/17-8134785-T-C?dataset=gnomad_r2_1). This variant is present in ClinVar, with several labs classifying this variant as Likely Benign or Benign (Variation ID: 241581). Evolutionary conservation and computational prediction tools for this variant are limited or unavailable. Of note, this is a silent variant and does not change the amino acid, reducing the probability that this variant is disease-causing. In summary, data on this variant suggests that this variant does not cause disease but requires further evidence. Therefore, this variant is classified as likely benign. -
Likely benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Jul 15, 2021	- -

not specified Benign:1

Benign, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Dec 11, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.94
CADD	Benign	0.099
DANN	Benign	0.37

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

Other links and lift over

dbSNP: rs200643329; hg19: chr17-8134785;