17-3640207-A-T

Position:

• chr17-3640207-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PP3_Strong PP5_Moderate

The NM_001374493.1(CTNS):​c.-356A>T variant causes a 5 prime UTR premature start codon gain change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: CTNS NM_001374493.1 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 4.24

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.986
• PP5: Variant 17-3640207-A-T is Pathogenic according to our data. Variant chr17-3640207-A-T is described in ClinVar as [Pathogenic]. Clinvar id is 1391189.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CTNS	NM_004937.3	c.1A>T	p.Met1?	initiator_codon_variant	3/12	ENST00000046640.9	NP_004928.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CTNS	ENST00000046640.9	c.1A>T	p.Met1?	initiator_codon_variant	3/12	1	NM_004937.3	ENSP00000046640.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 18, 2023

This sequence change affects the initiator methionine of the CTNS mRNA. The next in-frame methionine is located at codon 148. For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Ser139 amino acid residue in CTNS. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10556299, 15128704, 18178779, 19863563, 31074291). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that disruption of the initiator codon affects CTNS function (PMID: 15128704). Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. ClinVar contains an entry for this variant (Variation ID: 1391189). Disruption of the initiator codon has been observed in individual(s) with clinical features of cystinosis (PMID: 12442267, 19863563, 28793998). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.48
CADD	Benign	19
DANN	Benign	0.97
DEOGEN2	Uncertain	0.47	T;.;.;.;.
Eigen	Benign	-0.13
Eigen_PC	Benign	-0.021
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Uncertain	0.90	D;D;D;D;D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D
MetaSVM	Uncertain	0.34	D
PROVEAN	Benign	-0.42	N;N;N;N;.
REVEL	Uncertain	0.54
Sift	Pathogenic	0.0	D;D;D;D;.
Sift4G	Benign	0.14	T;T;D;D;T
Polyphen		0.0040	B;B;.;.;.
Vest4		0.91
MutPred		0.97		Loss of disorder (P = 0.0982);Loss of disorder (P = 0.0982);Loss of disorder (P = 0.0982);Loss of disorder (P = 0.0982);Loss of disorder (P = 0.0982);
MVP		0.94
ClinPred		0.99	D
GERP RS		5.0
Varity_R		0.82
gMVP		0.64

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr17-3543501;