rs777685454

Variant names:

Your query was ambiguous. Multiple possible variants found:

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1PM5PP2PP3_StrongPP5

The NM_000083.3(CLCN1):c.1606G>A(p.Val536Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000198 in 1,613,744 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V536A) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000019 ( 0 hom. )

Consequence

CLCN1
NM_000083.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4U:1

Conservation

PhyloP100: 9.99

Publications

9 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: Pathogenic. The variant received 10 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_000083.3

PM5

Other missense variant is known to change same aminoacid residue: Variant chr7-143341953-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 2926032.

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.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.974

PP5

Variant 7-143341952-G-A is Pathogenic according to our data. Variant chr7-143341952-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 447054.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CLCN1	NM_000083.3 link	c.1606G>A	p.Val536Ile	missense_variant	Exon 15 of 23	ENST00000343257.7	NP_000074.3
CLCN1	NR_046453.2 link	n.1561G>A		non_coding_transcript_exon_variant	Exon 14 of 22

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein
CLCN1	ENST00000343257.7 link	c.1606G>A	p.Val536Ile	missense_variant	Exon 15 of 23	1	NM_000083.3	ENSP00000339867.2
CLCN1	ENST00000432192.6 link	n.*891G>A		non_coding_transcript_exon_variant	Exon 15 of 23	1		ENSP00000395949.2
CLCN1	ENST00000432192.6 link	n.*891G>A		3_prime_UTR_variant	Exon 15 of 23	1		ENSP00000395949.2
CLCN1	ENST00000650516.2 link	c.1606G>A	p.Val536Ile	missense_variant	Exon 15 of 23			ENSP00000498052.2

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152198

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:

0.000188

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000239

AC:

AN:

251390

AF XY:

0.0000294

show subpopulations

Gnomad AFR exome

AF:

0.0000616

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000924

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000192

AC:

AN:

1461546

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

727084

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.0000383

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86238

European-Finnish (FIN)

AF:

0.0000562

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5512

European-Non Finnish (NFE)

AF:

0.0000180

AC:

AN:

1111992

Other (OTH)

AF:

0.0000166

AC:

AN:

60354

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152198

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74358

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41446

American (AMR)

AF:

0.00

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5198

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.000188

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.538

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000272

Hom.:

Bravo

AF:

0.0000189

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

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

Pathogenic:2

Jan 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 536 of the CLCN1 protein (p.Val536Ile). This variant is present in population databases (rs777685454, gnomAD 0.02%). This missense change has been observed in individual(s) with autosomal recessive myotonia congenita and late onset myotonia (PMID: 23152584, 29405036; 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: 447054). 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 CLCN1 protein function with a positive predictive value of 95%. This variant disrupts the p.Val536 amino acid residue in CLCN1. Other variant(s) that disrupt this residue have been observed in individuals with CLCN1-related conditions (PMID: 24304580), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. -

Jun 11, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:1Uncertain:1

Dec 07, 2016

Athena Diagnostics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 25, 2025

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Reported in a heterozygous state in an individual with a personal and family history of myotonia congenita (PMID: 28325641); Reported in patients with myotonia who also harbored as second CLCN1 variant, phase unknown (PMID: 23152584, 34529042); In silico analysis indicates that this missense variant does not alter protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 23152584, 31589614, 29405036, 34529042, 24304580, 28325641) -

Congenital myotonia, autosomal recessive form

Pathogenic:1

Neuberg Centre For Genomic Medicine, NCGM

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The CLCN1 c.1606G>A (p.Val536Ile) variant has been observed in individuals with autosomal recessive myotonia congenita and late onset myotonia (Raheem O et al, Ferese R et al). This p.Val536Ile variant has allele frequency of 0.002829% in the gnomAD and novel (not in any individuals) in 1000 genome database. It has been submitted to ClinVar with varying interpretations: Pathogenic/ Likely Pathogenic. The amino acid Val at position 536 is changed to a Ile changing protein sequence and it might alter its composition and physico-chemical properties. The amino acid change p.Val536Ile in CLCN1 is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.21

BayesDel_addAF

Pathogenic

0.22

BayesDel_noAF

Pathogenic

0.27

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.55

Eigen

Pathogenic

0.99

Eigen_PC

Pathogenic

0.97

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.98

M_CAP

Pathogenic

0.56

MetaRNN

Pathogenic

0.97

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.0

PhyloP100

PrimateAI

Uncertain

0.62

PROVEAN

Benign

-0.82

REVEL

Pathogenic

0.67

Sift

Uncertain

0.0030

Sift4G

Uncertain

0.0060

Polyphen

1.0

Vest4

0.90

MutPred

0.85

Loss of sheet (P = 0.0817);

MVP

0.97

MPC

0.66

ClinPred

0.69

GERP RS

5.9

Varity_R

0.68

gMVP

0.81

Mutation Taster

=17/83

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.14

Details are displayed if max score is > 0.2

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

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

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