17-3648932-G-C

Variant names:

• chr17-3648932-G-C
• rs1555561049
• NM_004937.3:c.225+1G>C

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_004937.3(CTNS):​c.225+1G>C variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000024 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: CTNS NM_004937.3 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.35
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• cystinosis

  Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
• nephropathic cystinosis

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp, G2P
• juvenile nephropathic cystinosis

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Genomics England PanelApp
• ocular cystinosis

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp
• nephropathic infantile cystinosis

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

LOC105371493 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 4.7, offset of 25, new splice context is: tggGTaggg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-3648932-G-C is Pathogenic according to our data. Variant chr17-3648932-G-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3239658.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004937.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CTNS	NM_004937.3	MANE Select	c.225+1G>C		splice_donor intron	N/A	NP_004928.2
	CTNS	NM_001031681.3		c.225+1G>C		splice_donor intron	N/A	NP_001026851.2
	CTNS	NM_001374492.1		c.225+1G>C		splice_donor intron	N/A	NP_001361421.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CTNS	ENST00000046640.9	TSL:1 MANE Select	c.225+1G>C		splice_donor intron	N/A	ENSP00000046640.4
	CTNS	ENST00000381870.8	TSL:1	c.225+1G>C		splice_donor intron	N/A	ENSP00000371294.3
	CTNS	ENST00000673965.1		c.225+1G>C		splice_donor intron	N/A	ENSP00000500995.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.0000244 AC: 35 AN: 1436886 Hom.: 0 Cov.: 29 AF XY: 0.0000154 AC XY: 11 AN XY: 716336

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.000121 AC: 4 AN: 32932

American (AMR) AF: 0.00 AC: 0 AN: 44700

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25978

East Asian (EAS) AF: 0.00 AC: 0 AN: 39568

South Asian (SAS) AF: 0.00 AC: 0 AN: 85768

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53362

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5732

European-Non Finnish (NFE) AF: 0.0000285 AC: 31 AN: 1089244

Other (OTH) AF: 0.00 AC: 0 AN: 59602

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Nephropathic cystinosis Pathogenic:1

Feb 01, 2024

Laboratory of Medical Genetics, National & Kapodistrian University of Athens

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Uncertain	0.10
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		6.3
GERP RS		5.1
Mutation Taster		=1/99	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.96		Position offset: -1

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

Other links and lift over

dbSNP: rs1555561049; hg19: chr17-3552226;