NM_000083.3:c.1748A>G

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP2

The NM_000083.3(CLCN1):c.1748A>G(p.Gln583Arg) variant causes a missense change. The variant allele was found at a frequency of 0.000052 in 1,614,094 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000053 ( 0 hom. )

Consequence

CLCN1
NM_000083.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 6.12

Publications

1 publications found

Variant links:

Genes affected

CLCN1 (HGNC:2019): (chloride voltage-gated channel 1) 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. The protein encoded by this gene regulates the electric excitability of the skeletal muscle membrane. Mutations in this gene cause two forms of inherited human muscle disorders: recessive generalized myotonia congenita (Becker) and dominant myotonia (Thomsen). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2012]

CLCN1 Gene-Disease associations (from GenCC):

myotonia congenita, autosomal dominant
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
myotonia congenita, autosomal recessive
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
Thomsen and Becker disease
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

CLCN1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 106 curated pathogenic missense variants (we use a threshold of 10). The gene has 18 curated benign missense variants. Gene score misZ: 0.21191 (below the threshold of 3.09). Trascript score misZ: 0.95247 (below the threshold of 3.09). GenCC associations: The gene is linked to myotonia congenita, autosomal dominant, myotonia congenita, autosomal recessive, Thomsen and Becker disease.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CLCN1	NM_000083.3 link	c.1748A>G	p.Gln583Arg	missense_variant	Exon 15 of 23	ENST00000343257.7	NP_000074.3	P35523
CLCN1	NR_046453.2 link	n.1703A>G		non_coding_transcript_exon_variant	Exon 14 of 22

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
CLCN1	ENST00000343257.7 link	c.1748A>G	p.Gln583Arg	missense_variant	Exon 15 of 23	1	NM_000083.3	ENSP00000339867.2	P35523
CLCN1	ENST00000432192.6 link	n.*1033A>G		non_coding_transcript_exon_variant	Exon 15 of 23	1		ENSP00000395949.2	H7C0N6
CLCN1	ENST00000432192.6 link	n.*1033A>G		3_prime_UTR_variant	Exon 15 of 23	1		ENSP00000395949.2	H7C0N6
CLCN1	ENST00000650516.2 link	c.1748A>G	p.Gln583Arg	missense_variant	Exon 15 of 23			ENSP00000498052.2	A0A3B3IU72

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152230

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000882

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251184

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000352

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000534

AC:

AN:

1461864

Hom.:

Cov.:

AF XY:

0.0000440

AC XY:

AN XY:

727230

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53392

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000701

AC:

AN:

1112010

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.474

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152230

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74366

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41466

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10632

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000882

AC:

AN:

68036

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.467

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000302

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Apr 29, 2021

Athena Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

May 20, 2021

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Uncertain:1

Jul 27, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: CLCN1 c.1748A>G (p.Gln583Arg) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.6e-05 in 251184 control chromosomes (i.e., 4 heterozygotes; gnomAD v2.1 Exomes dataset). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1748A>G has been reported in the literature in at least two compound heterozygous individuals affected with Myotonia congenita (e.g., Suetterlin_2022); segregation analysis confirmed a recessive pattern of inheritance in at least one of these individuals. These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function, finding that the variant affects the voltage dependence of activation in a manner in agreement with the variant being pathogenic in a recessive, but not a dominant setting (e.g., Suetterlin_2022). However, these findings do not allow convincing conclusions about the variant effect. The following publication was ascertained in the context of this evaluation (PMID: 34529042). Three submitters have reported clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Congenital myotonia, autosomal recessive form;C2936781:Congenital myotonia, autosomal dominant form

Uncertain:1

Jun 01, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 583 of the CLCN1 protein (p.Gln583Arg). This variant is present in population databases (rs747895358, gnomAD 0.004%). This missense change has been observed in individual(s) with clinical features of autosomal recessive CLCN1-related disease (PMID: 34529042; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 447057). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on CLCN1 protein function. Experimental studies have shown that this missense change affects CLCN1 function (PMID: 34529042). 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Uncertain

0.13

BayesDel_noAF

Uncertain

0.010

CADD

Pathogenic

(source)

DANN

Uncertain

0.98

DEOGEN2

Benign

0.12

Eigen

Uncertain

0.40

Eigen_PC

Uncertain

0.50

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Benign

0.84

M_CAP

Uncertain

0.11

MetaRNN

Uncertain

0.45

MetaSVM

Uncertain

0.15

MutationAssessor

Benign

0.63

PhyloP100

6.1

PrimateAI

Pathogenic

0.81

PROVEAN

Benign

-0.20

REVEL

Uncertain

0.47

Sift

Benign

1.0

Sift4G

Benign

0.67

Polyphen

1.0

Vest4

0.52

MutPred

0.34

Loss of methylation at K585 (P = 0.0648);

MVP

0.95

MPC

0.44

ClinPred

0.80

GERP RS

6.0

Varity_R

0.30

gMVP

0.79

Mutation Taster

=47/53

disease causing

(source)

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

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NM_000083.3:c.1748A>G

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over