rs80356691

Variant names:

• chr7-143330847-C-T
• rs80356691
• NM_000083.3:c.929C>T

Variant summary

Our verdict is Pathogenic. The variant received 21 ACMG points: 21P and 0B. PS3 PM1 PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_000083.3(CLCN1):​c.929C>T​(p.Thr310Met) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,614,076 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 Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV006305278: Published functional studies demonstrate this variants alters open probability of the common gate via reduced opening rate (PMID:12390967, 12566541)" and additional evidence is available in ClinVar. Synonymous variant affecting the same amino acid position (i.e. T310T) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CLCN1 NM_000083.3 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:6 O:1
• Conservation: PhyloP100: 6.14
• Publications: 15 publications found

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

ACMG classification

Our verdict: Pathogenic. The variant received 21 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV006305278: Published functional studies demonstrate this variants alters open probability of the common gate via reduced opening rate (PMID: 12390967, 12566541); SCV002073049: Functional studies suggest a damaging effect by affecting the opening rate (Duffield M et al).; SCV003264555: Experimental studies have shown that this missense change affects CLCN1 function (PMID: 12390967, 12566541).; SCV005205260: Experimental studies show that this variant impacts CIC-1 gating in vitro (e.g. Wu_2002, Duffield_2003).
• PM1: In a hotspot region, there are 11 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000083.3
• PM2: Very rare variant in population databases, with high coverage
• 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, 0.94
• PP5: Variant 7-143330847-C-T is Pathogenic according to our data. Variant chr7-143330847-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 21051.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.929C>T	p.Thr310Met	missense	Exon 8 of 23	NP_000074.3	P35523
	CLCN1	NR_046453.2		n.1034C>T		non_coding_transcript_exon	Exon 8 of 22

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CLCN1	ENST00000343257.7	TSL:1 MANE Select	c.929C>T	p.Thr310Met	missense	Exon 8 of 23	ENSP00000339867.2	P35523
	CLCN1	ENST00000432192.6	TSL:1	n.*214C>T		non_coding_transcript_exon	Exon 8 of 23	ENSP00000395949.2	H7C0N6
	CLCN1	ENST00000455478.6	TSL:1	n.*214C>T		non_coding_transcript_exon	Exon 7 of 7	ENSP00000400027.2	H7C1F4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152194 Hom.: 0 Cov.: 32

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00 AC: 0 AN: 251414 AF XY: 0.00

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461882 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727248

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112008

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152194 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74360

African (AFR) AF: 0.00 AC: 0 AN: 41436

American (AMR) AF: 0.00 AC: 0 AN: 15276

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5190

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68044

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	Congenital myotonia, autosomal recessive form;C2936781:Congenital myotonia, autosomal dominant form (2)
2	-	-	not provided (2)
1	-	-	Congenital myotonia, autosomal dominant form (1)
1	-	-	Congenital myotonia, autosomal recessive form (1)
-	-	-	Batten-Turner congenital myopathy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.33
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.71	D
Eigen	Uncertain	0.49
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.47	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Uncertain	0.73	D
MutationAssessor	Benign	1.0	L
PhyloP100		6.1
PrimateAI	Uncertain	0.76	T
PROVEAN	Uncertain	-3.5	D
REVEL	Pathogenic	0.89
Sift	Uncertain	0.0040	D
Sift4G	Uncertain	0.0070	D
Polyphen		1.0	D
Vest4		0.84
MutPred		0.82		Loss of catalytic residue at T310 (P = 0.0895)
MVP		0.98
MPC		0.72
ClinPred		0.98	D
GERP RS		4.6
Varity_R		0.65
gMVP		0.76
Mutation Taster		=14/86	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs80356691; hg19: chr7-143027940;