rs759623796

Positions:

• chr17-3658081-TCGTGGCTGCAGTGGGAGTGACCA-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_004937.3(CTNS):​c.771_793del​(p.Gly258SerfsTer30) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000093 in 1,612,260 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000089 (0 hom.)
• Consequence: CTNS NM_004937.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:10
• Conservation: PhyloP100: 7.44

Genes affected

CTNS (HGNC:2518): (cystinosin, lysosomal cystine transporter) This gene encodes a seven-transmembrane domain protein that functions to transport cystine out of lysosomes. Its activity is driven by the H+ electrochemical gradient of the lysosomal membrane. Mutations in this gene cause cystinosis, a lysosomal storage disorder. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2009]

CTNS-AS1 (HGNC:56090): (CTNS antisense RNA 1)

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-3658081-TCGTGGCTGCAGTGGGAGTGACCA-T is Pathogenic according to our data. Variant chr17-3658081-TCGTGGCTGCAGTGGGAGTGACCA-T is described in ClinVar as [Pathogenic]. Clinvar id is 496276.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CTNS	NM_004937.3	c.771_793del	p.Gly258SerfsTer30	frameshift_variant	10/12	ENST00000046640.9	NP_004928.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CTNS	ENST00000046640.9	c.771_793del	p.Gly258SerfsTer30	frameshift_variant	10/12	1	NM_004937.3	ENSP00000046640	P1
CTNS-AS1	ENST00000575741.1			non_coding_transcript_exon_variant	1/3	5

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 152072 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000279 AC: 7 AN: 251296 Hom.: 0 AF XY: 0.0000294 AC XY: 4 AN XY: 135878

Gnomad AFR exome AF: 0.0000616

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000163

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000890 AC: 13 AN: 1460070 Hom.: 0 AF XY: 0.0000110 AC XY: 8 AN XY: 726384

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: 0.000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152190 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74420

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000151

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Nephropathic cystinosis Pathogenic:5

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Dec 25, 2022	- -
Likely pathogenic, no assertion criteria provided	clinical testing	Counsyl	Aug 16, 2014	- -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center	Mar 25, 2024	- -
Pathogenic, criteria provided, single submitter	clinical testing	Neuberg Centre For Genomic Medicine, NCGM	May 20, 2023	The observed frameshift c.771_793del (p.Gly258SerfsTer30) variant in CTNS gene has been reported in homozygous state in individual(s) affected with cystinosis (Chkioua L et al., 2015; Ghazi F, et. al., 2017). The p.Gly258SerfsTer30 variant is present with allele frequency 0.003% in gnomAD Exomes database. This variant has been submitted to the ClinVar database as Likely Pathogenic / Pathogenic (multiple submitters). This variant causes a frameshift starting with codon Glycine 258, changes this amino acid to Serine residue, and creates a premature Stop codon at position 30 of the new reading frame, denoted p.Gly258SerfsTer30. This variant is predicted to cause loss of normal protein function through protein truncation. Loss-of-function variants in CTNS are known to be pathogenic (Elmonem MA, et. al., 2016). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Johns Hopkins Genomics, Johns Hopkins University	Apr 26, 2021	This 23 bp deletion in CTNS has been previously reported in individuals with nephropathic cystinosis. This CTNS variant (rs759623796) is rare (<0.1%) in a large population dataset (gnomAD: 7/251296 total alleles; 0.003%; no homozygotes) and there is an entry in ClinVar. This frameshift variant results in a premature stop codon in exon 11 likely leading to nonsense-mediated decay and lack of protein production. We consider this variant to be pathogenic. -

Cystinosis Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Centogene AG - the Rare Disease Company	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jul 05, 2017	Variant summary: The variant results in the deletion of a 23 nucleotides leading to a termination codon at position 288 of CTNS. The variant was present at a low frequency in the large and broad cohorts of the ExAC project (3/121,076 chromosomes) while it was observed in multiple CTNS patients in the literature. Considering all evidence, the variant was classified as pathogenic. -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Jan 26, 2021	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Revvity Omics, Revvity

Dec 02, 2021

- -

Juvenile nephropathic cystinosis;C0950123:Inborn genetic diseases;C2931013:Ocular cystinosis Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 05, 2023

For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 496276). This variant is also known as c.1109_1131del23. This premature translational stop signal has been observed in individuals with cystinosis (PMID: 10556299, 26266097). This variant is present in population databases (rs759623796, gnomAD 0.02%). This sequence change creates a premature translational stop signal (p.Gly258Serfs*30) in the CTNS gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CTNS are known to be pathogenic (PMID: 9537412, 27102039). -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs759623796; hg19: chr17-3561375;