dbSNP rs80356702: CLCN1:p.Arg317Gln (chr7-143330868-G-A) – ACMG Classification: Pathogenic (19 pts)

Variant summary

Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PS3PM1PM5PP2PP3_ModeratePP5_Very_Strong

The NM_000083.3(CLCN1):c.950G>A(p.Arg317Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,614,030 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 Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV005400980: Experimental studies indicate that p.Arg317Gln shifts the gating threshold to a positive voltage thus altering channel gating and preventing repolarization of the channel (Pusch et al., 1995)." and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R317P) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

CLCN1
NM_000083.3 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:16O:2

Conservation

PhyloP100: 9.99

Publications

11 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 19 ACMG points.

PS3

PS3 evidence extracted from ClinVar submissions: SCV005400980: Experimental studies indicate that p.Arg317Gln shifts the gating threshold to a positive voltage thus altering channel gating and preventing repolarization of the channel (Pusch et al., 1995).; SCV000612809: Assessment of experimental evidence suggests this variant results in abnormal protein function. (PMID: 8845168); SCV002044125: Published functional studies indicate that R317Q shifts the gating threshold to a positive voltage thus altering channel gating and preventing repolarization of the channel (PMID: 8845168); SCV000931840: Experimental studies have shown that this missense change affects CLCN1 function (PMID: 8845168).

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000083.3

PM5

Other missense variant is known to change same aminoacid residue: Variant chr7-143330868-G-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1508818.Status of the report is criteria_provided_single_submitter, 1 stars.

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, 0.898

PP5

Variant 7-143330868-G-A is Pathogenic according to our data. Variant chr7-143330868-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 17542.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000083.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CLCN1	NM_000083.3	MANE Select	c.950G>A	p.Arg317Gln	missense	Exon 8 of 23	NP_000074.3	P35523
	CLCN1	NR_046453.2		n.1055G>A		non_coding_transcript_exon	Exon 8 of 22

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
CLCN1	ENST00000343257.7	TSL:1 MANE Select	c.950G>A	p.Arg317Gln	missense	Exon 8 of 23	ENSP00000339867.2	P35523
CLCN1	ENST00000432192.6	TSL:1	n.*235G>A		non_coding_transcript_exon	Exon 8 of 23	ENSP00000395949.2	H7C0N6
CLCN1	ENST00000455478.6	TSL:1	n.*235G>A		non_coding_transcript_exon	Exon 7 of 7	ENSP00000400027.2	H7C1F4

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152140

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251428

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461890

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.0000299

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:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1112010

Other (OTH)

AF:

0.00

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.455

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:

0.00000657

AC:

AN:

152140

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74328

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41416

American (AMR)

AF:

0.00

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10604

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000235

Hom.:

Bravo

AF:

0.00000756

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

ClinVar submissions

Significance:Pathogenic/Likely pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Congenital myotonia, autosomal dominant form (6)

Congenital myotonia, autosomal recessive form (4)

not provided (3)

Congenital myotonia, autosomal recessive form;C2936781:Congenital myotonia, autosomal dominant form (3)

Limb pain;C0037763:Muscle spasm;C0149931:Migraine;C0233794:Memory impairment;C4021727:EMG: neuropathic changes;C4025576:EMG: myotonic runs (1)

Batten-Turner congenital myopathy (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.68

BayesDel_addAF

Pathogenic

0.46

BayesDel_noAF

Pathogenic

0.43

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.80

Eigen

Pathogenic

0.76

Eigen_PC

Pathogenic

0.69

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.99

M_CAP

Pathogenic

0.54

MetaRNN

Pathogenic

0.90

MetaSVM

Pathogenic

0.97

MutationAssessor

Uncertain

2.3

PhyloP100

PrimateAI

Pathogenic

0.81

PROVEAN

Uncertain

-3.7

REVEL

Pathogenic

0.90

Sift

Uncertain

0.018

Sift4G

Uncertain

0.020

Polyphen

1.0

Vest4

0.92

MVP

0.99

MPC

0.79

ClinPred

1.0

GERP RS

4.6

Varity_R

0.85

gMVP

0.84

Mutation Taster

=5/95

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

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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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over