NM_004937.3:c.225+5_225+8delGTAA

Variant names:

• chr17-3648929-GAAGT-G
• rs1555561048
• NM_004937.3:c.225+5_225+8delGTAA

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM2 PP3_Moderate PP5_Very_Strong

The NM_004937.3(CTNS):​c.225+5_225+8delGTAA variant causes a splice region, intron change. The variant was absent in control chromosomes in GnomAD project. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CTNS NM_004937.3 splice_region, intron
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 U: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.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 17-3648929-GAAGT-G is Pathogenic according to our data. Variant chr17-3648929-GAAGT-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 550829.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 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+5_225+8delGTAA		splice_region intron	N/A	NP_004928.2
	CTNS	NM_001031681.3		c.225+5_225+8delGTAA		splice_region intron	N/A	NP_001026851.2
	CTNS	NM_001374492.1		c.225+5_225+8delGTAA		splice_region 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.224_225+2delAAGT	p.Glu75ValfsTer7	frameshift splice_donor splice_region intron	Exon 5 of 12	ENSP00000046640.4
	CTNS	ENST00000381870.8	TSL:1	c.224_225+2delAAGT	p.Glu75ValfsTer7	frameshift splice_donor splice_region intron	Exon 5 of 13	ENSP00000371294.3
	CTNS	ENST00000488623.6	TSL:3	c.-504_-503+2delAAGT		splice_region	Exon 4 of 11	ENSP00000501016.1

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Nephropathic cystinosis Pathogenic:1 Uncertain:1

Feb 24, 2017

Counsyl

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.

Mar 18, 2024

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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

Oct 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 5 of the CTNS gene. It does not directly change the encoded amino acid sequence of the CTNS protein. RNA analysis indicates that this variant induces altered splicing and may result in an absent or altered protein product. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with cystinosis (PMID: 12442267). This variant is also known as 564+1del4. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant results in skipping of exons 4 and 5 , and produces a non-functional protein and/or introduces a premature termination codon (PMID: 12442267). This variant disrupts the c.225+5 nucleotide in the CTNS gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 11708862). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		6.3
Mutation Taster		=1/199	disease causing (fs/PTC)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.96		Position offset: 2

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

Other links and lift over

dbSNP: rs1555561048; hg19: chr17-3552223;