4-169687707-A-G

Position:

• chr4-169687707-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_001829.4(CLCN3):​c.368A>G​(p.Tyr123Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,458,312 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CLCN3 NM_001829.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.22

Genes affected

CLCN3 (HGNC:2021): (chloride voltage-gated channel 3) This gene encodes a member of the voltage-gated chloride channel (ClC) family. The encoded protein is present in all cell types and localized in plasma membranes and in intracellular vesicles. It is a multi-pass membrane protein which contains a ClC domain and two additional C-terminal CBS (cystathionine beta-synthase) domains. The ClC domain catalyzes the selective flow of Cl- ions across cell membranes, and the CBS domain may have a regulatory function. This protein plays a role in both acidification and transmitter loading of GABAergic synaptic vesicles, and in smooth muscle cell activation and neointima formation. This protein is required for lysophosphatidic acid (LPA)-activated Cl- current activity and fibroblast-to-myofibroblast differentiation. The protein activity is regulated by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in glioma cells. Multiple alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Aug 2011]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the CLCN3 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 11 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 4.3745 (above the threshold of 3.09). Trascript score misZ: 5.1954 (above the threshold of 3.09). GenCC associations: The gene is linked to neurodevelopmental disorder with seizures and brain abnormalities, complex neurodevelopmental disorder, neurodevelopmental disorder with hypotonia and brain abnormalities.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.795

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CLCN3	NM_001829.4	c.368A>G	p.Tyr123Cys	missense_variant	4/13	ENST00000513761.6	NP_001820.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CLCN3	ENST00000513761.6	c.368A>G	p.Tyr123Cys	missense_variant	4/13	1	NM_001829.4	ENSP00000424603.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1458312 Hom.: 0 Cov.: 28 AF XY: 0.00000276 AC XY: 2 AN XY: 725388

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000117

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.01e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 20, 2024

The c.368A>G (p.Y123C) alteration is located in exon 1 (coding exon 1) of the CLCN3 gene. This alteration results from a A to G substitution at nucleotide position 368, causing the tyrosine (Y) at amino acid position 123 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.76	.;D;.;.;T;.;.;.
Eigen	Uncertain	0.38
Eigen_PC	Uncertain	0.37
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.88	D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.22	D
MetaRNN	Pathogenic	0.79	D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.49	D
MutationAssessor	Uncertain	2.6	.;M;M;M;.;.;.;.
PrimateAI	Pathogenic	0.85	D
PROVEAN	Uncertain	-3.4	D;D;D;D;D;D;.;D
REVEL	Pathogenic	0.82
Sift	Benign	0.18	T;T;T;T;T;T;.;T
Sift4G	Benign	0.18	T;T;T;T;T;T;T;T
Polyphen		0.89, 0.93	.;P;P;.;.;P;.;.
Vest4		0.45, 0.46, 0.43, 0.45, 0.46
MutPred		0.60		Loss of helix (P = 0.0196);Loss of helix (P = 0.0196);Loss of helix (P = 0.0196);Loss of helix (P = 0.0196);Loss of helix (P = 0.0196);.;.;.;
MVP		0.94
MPC		2.3
ClinPred		0.98	D
GERP RS		4.1
Varity_R		0.20
gMVP		0.98

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: rs1581251098; hg19: chr4-170608858;