X-18642011-C-T

Position:

• chrX-18642011-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C223G) has been classified as Likely 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 18 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000330.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrX-18642012-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1511265.Status of the report is criteria_provided_single_submitter, 1 stars.
• 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/exons	MANE	UniProt
RS1	NM_000330.4	c.668G>A	p.Cys223Tyr	missense_variant	6/6	ENST00000379984.4
RS1	XM_047442337.1	c.572G>A	p.Cys191Tyr	missense_variant	4/4
CDKL5	NM_001037343.2	c.2714-3996C>T		intron_variant
CDKL5	NM_003159.3	c.2714-3996C>T		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RS1	ENST00000379984.4	c.668G>A	p.Cys223Tyr	missense_variant	6/6	1	NM_000330.4	P1
CDKL5	ENST00000379989.6	c.2714-3996C>T		intron_variant		1
CDKL5	ENST00000379996.7	c.2714-3996C>T		intron_variant		1
RS1	ENST00000476595.1	n.1159G>A		non_coding_transcript_exon_variant	5/5	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

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 17, 2023	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). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt RS1 protein function. 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; Invitae). 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. -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Sep 17, 2015	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. -

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
MutationTaster	Benign	1.0	D;D;D
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;