rs1555976973

Variant names:

• chrX-10212653-G-A
• rs1555976973
• NM_001830.4:c.1576G>A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PP2 PP3_Strong PP5

The NM_001830.4(CLCN4):​c.1576G>A​(p.Gly526Ser) variant causes a missense, splice region 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. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. G526G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 23)
• Consequence: CLCN4 NM_001830.4 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 9.80

Genes affected

CLCN4 (HGNC:2022): (chloride voltage-gated channel 4) The CLCN family of voltage-dependent chloride channel genes comprises nine members (CLCN1-7, Ka and Kb) which demonstrate quite diverse functional characteristics while sharing significant sequence homology. Chloride channel 4 has an evolutionary conserved CpG island and is conserved in both mouse and hamster. This gene is mapped in close proximity to APXL (Apical protein Xenopus laevis-like) and OA1 (Ocular albinism type I), which are both located on the human X chromosome at band p22.3. The physiological role of chloride channel 4 remains unknown but may contribute to the pathogenesis of neuronal disorders. Alternate splicing results in two transcript variants that encode different proteins. [provided by RefSeq, Mar 2012]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the CLCN4 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 25 curated pathogenic missense variants (we use a threshold of 10). The gene has 21 curated benign missense variants. Gene score misZ: 4.5166 (above the threshold of 3.09). GenCC associations: The gene is linked to non-syndromic X-linked intellectual disability, intellectual disability, X-linked 49.
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant X-10212653-G-A is Pathogenic according to our data. Variant chrX-10212653-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 495273.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=1, Likely_pathogenic=1}. Variant chrX-10212653-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CLCN4	NM_001830.4	c.1576G>A	p.Gly526Ser	missense_variant, splice_region_variant	Exon 10 of 13	ENST00000380833.9	NP_001821.2
CLCN4	NM_001256944.2	c.1294G>A	p.Gly432Ser	missense_variant, splice_region_variant	Exon 8 of 11		NP_001243873.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CLCN4	ENST00000380833.9	c.1576G>A	p.Gly526Ser	missense_variant, splice_region_variant	Exon 10 of 13	1	NM_001830.4	ENSP00000370213.4

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 23

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1 Uncertain:1

Nov 18, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Alters the last nucleotide of the exon and is predicted to destroy the splice donor site and result in aberrant splicing, although in the absence of functional evidence the actual effect of this sequence change is unknown; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 31780880, 36385166) -

Jan 12, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 526 of the CLCN4 protein (p.Gly526Ser). This variant also falls at the last nucleotide of exon 10, which is part of the consensus splice site for this exon. This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of CLCN4-related conditions (PMID: 31780880, 36385166). ClinVar contains an entry for this variant (Variation ID: 495273). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on CLCN4 function (PMID: 36385166). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Intellectual disability, X-linked 49 Pathogenic:1

Jan 01, 2018

NeuroMeGen, Hospital Clinico Santiago de Compostela

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.61
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	34
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	.;D;D
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.96	D;D;D
MetaSVM	Pathogenic	0.82	D
MutationAssessor	Benign	1.9	.;L;.
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-4.9	D;D;D
REVEL	Pathogenic	0.91
Sift	Benign	0.077	T;T;T
Sift4G	Benign	0.23	T;T;T
Polyphen		0.87	.;P;.
Vest4		0.89
MutPred		0.68		.;Gain of glycosylation at G526 (P = 0.0746);.;
MVP		1.0
MPC		2.1
ClinPred		0.98	D
GERP RS		5.7
Varity_R		0.72
gMVP		0.92

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.54		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.54		Position offset: -22
DS_DL_spliceai		0.20		Position offset: 0

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555976973; hg19: chrX-10180693; COSMIC: COSV66465542;