X-18642011-C-T

Variant names:

• chrX-18642011-C-T
• rs1057517816
• NM_000330.4:c.668G>A

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_000330.4(RS1):​c.668G>A​(p.Cys223Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. 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: 23)
• Consequence: RS1 NM_000330.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.57

Genes affected

RS1 (HGNC:10457): (retinoschisin 1) This gene encodes an extracellular protein that plays a crucial role in the cellular organization of the retina. The encoded protein is assembled and secreted from photoreceptors and bipolar cells as a homo-oligomeric protein complex. Mutations in this gene are responsible for X-linked retinoschisis, a common, early-onset macular degeneration in males that results in a splitting of the inner layers of the retina and severe loss in vision. [provided by RefSeq, Oct 2008]

CDKL5 (HGNC:11411): (cyclin dependent kinase like 5) This gene is a member of Ser/Thr protein kinase family and encodes a phosphorylated protein with protein kinase activity. Mutations in this gene have been associated with X-linked infantile spasm syndrome (ISSX), also known as X-linked West syndrome, and Rett syndrome (RTT). Alternate transcriptional splice variants have been characterized. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a disulfide_bond Interchain (with C-59) (size 0) in uniprot entity XLRS1_HUMAN
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.987
• PP5: Variant X-18642011-C-T is Pathogenic according to our data. Variant chrX-18642011-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 372497.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chrX-18642011-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RS1	NM_000330.4	c.668G>A	p.Cys223Tyr	missense_variant	Exon 6 of 6	ENST00000379984.4	NP_000321.1
RS1	XM_047442337.1	c.572G>A	p.Cys191Tyr	missense_variant	Exon 4 of 4		XP_047298293.1
CDKL5	NM_001037343.2	c.2714-3996C>T		intron_variant	Intron 19 of 21		NP_001032420.1
CDKL5	NM_003159.3	c.2714-3996C>T		intron_variant	Intron 18 of 20		NP_003150.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RS1	ENST00000379984.4	c.668G>A	p.Cys223Tyr	missense_variant	Exon 6 of 6	1	NM_000330.4	ENSP00000369320.3
CDKL5	ENST00000379989.6	c.2714-3996C>T		intron_variant	Intron 19 of 21	1		ENSP00000369325.3
CDKL5	ENST00000379996.7	c.2714-3996C>T		intron_variant	Intron 18 of 20	1		ENSP00000369332.3
RS1	ENST00000476595.1	n.1159G>A		non_coding_transcript_exon_variant	Exon 5 of 5	1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Sep 17, 2015

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The C223Y missense variant in the RS1 gene has been reported previously in association with X-linked juvenile retinoschisis (Sergeev et al., 2010). Molecular modeling indicated that the C223Y substitution breaks a disulfide bond within the discoidin domain of the protein, decreasing stability of this domain and possibly affecting protein conformation (Sergeev et al., 2010). Therefore, we interpret C223Y as a pathogenic variant. -

Jan 21, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 223 of the RS1 protein (p.Cys223Tyr). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with retinoschisis (PMID: 20061330, 22245991). ClinVar contains an entry for this variant (Variation ID: 372497). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt RS1 protein function with a positive predictive value of 95%. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. This variant disrupts the p.Cys223 amino acid residue in RS1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10533068, 16361673, 30652005; internal data). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.72	D
BayesDel_noAF	Pathogenic	0.80
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.80	D
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.54	T
M_CAP	Pathogenic	0.96	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.4	M
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-3.2	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.87
MutPred		0.86		Gain of disorder (P = 0.0667);
MVP		1.0
MPC		2.0
ClinPred		0.99	D
GERP RS		5.6
Varity_R		0.88
gMVP		1.0

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: rs1057517816; hg19: chrX-18660131;