rs202179484

Variant names:

• chr7-143330813-G-C
• rs202179484
• NM_000083.3:c.895G>C

Your query was ambiguous. Multiple possible variants found:

• chr7-143330813-G-C
• chr7-143330813-G-A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PS3 PM1 PP2 PP3_Moderate PP5

The NM_000083.3(CLCN1):​c.895G>C​(p.Val299Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000558 in 1,614,086 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). ClinVar reports functional evidence for this variant: "SCV005399623: Patch clamp assays in xenopus oocytes demonstrated a reduction in channel activities when expressed both as a homomer or in heterozygous state (co-expressed as mutant + WT) (PMID:34529042).". Synonymous variant affecting the same amino acid position (i.e. V299V) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: CLCN1 NM_000083.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4 U:3
• Conservation: PhyloP100: 9.99
• Publications: 2 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 10 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV005399623: Patch clamp assays in xenopus oocytes demonstrated a reduction in channel activities when expressed both as a homomer or in heterozygous state (co-expressed as mutant + WT) (PMID: 34529042).
• PM1: In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 6 uncertain in NM_000083.3
• 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, 0.932
• PP5: Variant 7-143330813-G-C is Pathogenic according to our data. Variant chr7-143330813-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 447073.

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.895G>C	p.Val299Leu	missense	Exon 8 of 23	NP_000074.3	P35523
	CLCN1	NR_046453.2		n.1000G>C		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.895G>C	p.Val299Leu	missense	Exon 8 of 23	ENSP00000339867.2	P35523
	CLCN1	ENST00000432192.6	TSL:1	n.*180G>C		non_coding_transcript_exon	Exon 8 of 23	ENSP00000395949.2	H7C0N6
	CLCN1	ENST00000455478.6	TSL:1	n.*180G>C		non_coding_transcript_exon	Exon 7 of 7	ENSP00000400027.2	H7C1F4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152200 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: 0.00

Gnomad OTH AF: 0.000478

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251404 AF XY: 0.00000736

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: 0.00000547 AC: 8 AN: 1461886 Hom.: 0 Cov.: 32 AF XY: 0.00000688 AC XY: 5 AN XY: 727242

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

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

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

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.000173 AC: 1 AN: 5766

European-Non Finnish (NFE) AF: 0.00000540 AC: 6 AN: 1112012

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

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152200 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74362

African (AFR) AF: 0.00 AC: 0 AN: 41454

American (AMR) AF: 0.00 AC: 0 AN: 15280

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5196

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10616

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68036

Other (OTH) AF: 0.000478 AC: 1 AN: 2092

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000113

EpiCase AF: 0.000109

EpiControl AF: 0.00

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
2	-	-	Congenital myotonia, autosomal recessive form (2)
1	1	-	not provided (2)
1	-	-	Abnormality of the musculature (1)
-	1	-	Congenital myotonia, autosomal dominant form (1)
-	1	-	Congenital myotonia, autosomal recessive form;C2936781:Congenital myotonia, autosomal dominant form (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.78
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.43
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.76	D
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.54
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.43	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Uncertain	0.74	D
MutationAssessor	Benign	1.6	L
PhyloP100		10
PrimateAI	Pathogenic	0.90	D
PROVEAN	Uncertain	-2.5	D
REVEL	Pathogenic	0.80
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.0050	D
Polyphen		1.0	D
Vest4		0.88
MutPred		0.84		Gain of helix (P = 0.132)
MVP		0.97
MPC		0.65
ClinPred		0.96	D
GERP RS		4.6
Varity_R		0.82
gMVP		0.80
Mutation Taster		=12/88	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: rs202179484; hg19: chr7-143027906;